Explanation:

The correct answer is:

B. osmosis

Topic: Cell Transport Processes

The diagram shows osmosis. This is the movement of water across a semi-permeable membrane. Water moves from where there is more water (less salt) to where there is less water (more salt). The diagram shows water moving through the membrane to balance out the salt levels on both sides.

Here's why the other answers are wrong:

• A. active transport: This process uses energy to move substances against their natural flow. The diagram shows water moving naturally without energy, so this is not active transport.


• C. plasmolysis: This is when plant cells shrink because they lose water. The diagram does not show plant cells or cell shrinking.


• D. aerobic respiration: This is the process cells use to make energy with oxygen. The diagram shows water movement, not energy production.

Explanation:

The correct answer is:

B. shows the movement of solvent through a semi-permeable membrane to a region of higher concentration of solutes

Topic: Osmosis Process

Diagram B shows the result after osmosis happens. The solvent (water) moved through the membrane from the left side to the right side where there was more salt. This movement continues until the salt levels become more equal on both sides. You can see the water level is now higher on the right side.

Here's why the other answers are wrong:

• A. is the control: Diagram A is the control (starting point). Diagram B shows what happens after the process, so it is not the control.


• C. shows the movement of solutes through a semi-permeable membrane to a region of higher concentration of solutes: The salt molecules do not move through the membrane. Only water moves. The membrane lets water pass but blocks salt.


• D. does not take place in plants: Osmosis happens in all living things, including plants. Plants use osmosis to move water from roots to leaves.

Explanation:

The correct answer is:

A. Carbon dioxide and ethanol

In yeast cells, when there is no oxygen, glucose is turned into carbon dioxide and ethanol. This is called alcoholic fermentation. It gives energy to the yeast and is used to make things like bread and alcohol.

Here's why the other answers are wrong:

• B. Carbon dioxide and lactic acid: This happens in animal muscles when there is no oxygen, not in yeast.


• C. Carbon dioxide and water: This is part of breathing with oxygen (aerobic respiration), not without oxygen.


• D. Ethanol and lactic acid: Yeast makes ethanol, but it doesn’t make lactic acid. Lactic acid is made in muscles, not in yeast.

Explanation:

The correct answer is:

D. Orange

Epigeal germination is when the seed leaves (cotyledons) come above the ground during sprouting. In orange plants, part of the stem (hypocotyl) grows longer and pushes the seed leaves above the soil.

Here is why the other plants are not correct:

• A. Rice: Rice keeps the seed leaves underground during sprouting (hypogeal germination).


• B. Maize: Maize also keeps the seed leaves underground (hypogeal germination).


• C. Yam: Yam grows from a tuber, not a seed, so it does not have epigeal germination.

Explanation:

The correct answer is:

C. Enhance attachment of muscles on bones

The protrusions on bones (like bumps or ridges) are places where muscles, tendons, and ligaments can attach. This helps muscles pull on the bones during movement. Without these points, it would be hard for muscles to move the bones properly.

Here's why the other answers are wrong:

• A. Increase the surface area of the bone: Protrusions do not just increase surface area; they mainly help with muscle attachment.


• B. Are covered with cartilage to reduce friction: Cartilage reduces friction, but protrusions are not mainly about reducing friction.


• D. Strengthen the bones: Protrusions do not make bones stronger, but they help muscles attach and move bones better.

Explanation:

The correct answer is:

A. Arthropods

Arthropods, like insects, spiders, and crabs, have an open circulatory system. This means their blood (called hemolymph) doesn’t stay inside blood vessels. Instead, it flows freely through the body and directly touches the organs.

Here’s why the other options are wrong:

• B. Aves (birds): Birds have a closed circulatory system, where blood stays in vessels.


• C. Annelids (worms): Worms also have a closed circulatory system.


• D. Amphibians: Amphibians, like frogs, have a closed circulatory system too.

Explanation:

The correct answer is:

D. gill

Topic: Respiratory Structures in Aquatic Animals

The structure shown is a gill. Gills are special body parts that help water animals breathe. They have a feathery shape with many thin parts that give lots of surface area for taking oxygen from water and getting rid of carbon dioxide.

Here's why the other answers are wrong:

• A. scale: Scales are flat, hard pieces that cover and protect fish skin, not feathery breathing parts.


• B. pinna: A pinna is the outer ear part in mammals, not a water breathing structure.


• C. wing: Wings are for flying and have solid surfaces with feathers or membranes, not thin filaments for breathing.

Explanation:

The correct answer is:

B. gaseous exchange

Topic: Gill Function and Gas Exchange

Part I points to the gill filaments. These thin, finger-like parts are where gas exchange happens. They have lots of blood vessels close to the surface, so oxygen can move from the water into the blood, and carbon dioxide can move from the blood into the water.

Here's why the other answers are wrong:

• A. sieving particles in flowing water: Gill filaments are for breathing, not filtering food particles from water.


• C. shielding against sunlight: Gill filaments are inside the body or under protective covers, they do not block sunlight.


• D. preventing desiccation: Desiccation means drying out, but gill filaments need to stay wet to work and are not for preventing water loss.

Explanation:

The correct answer is:

C. The temperature of the environment rises above 38°C

When the temperature goes above 38°C, your body sweats more to cool down. As a result, your kidneys make less urine to keep more water in the body. This helps keep the right balance of water in your body.

Here’s why the other answers are wrong:

• A. A large volume of fruit juice is drunk: Drinking fruit juice doesn't directly affect how much urine your kidneys make.


• B. A large volume of water is drunk: Drinking a lot of water actually makes the kidneys produce more urine to get rid of the extra water.


• D. Antidiuretic hormone is not secreted: If this hormone isn't secreted, it usually causes more urine to be made, not less.

Explanation:

The correct answer is:

D. Chemical transmitters

Impulses move across the synapse (the gap between two nerve cells) using chemicals called neurotransmitters. These chemicals are released by one nerve cell and help send the signal to the next cell, allowing the message to pass through the nervous system.

Here’s why the other answers are wrong:

• A. Synaptic sparks: There are no sparks involved in how impulses are sent across synapses.


• B. Electronic waves: Impulses are not sent as electronic waves, but through chemicals.


• C. Electrical currents: While electrical impulses travel along nerves, the actual transmission across synapses is done with chemicals, not electrical currents.

Explanation:

The correct answer is:

A. Semi-circular canals

The semi-circular canals in the ear help you keep your balance and know which way your head is moving. When a boxer is hit and falls, it’s usually because the semi-circular canals don’t work properly for a short time. After a few seconds, the balance comes back, and the person can stand up.

Here’s why the other answers are wrong:

• B. Ossicles: These are the tiny bones in the ear that help with hearing, not balance.


• C. Cochlea: The cochlea helps with hearing, not balance.


• D. Eustachian tube: This tube helps balance pressure in the ear, but it doesn't control your balance directly.

Explanation:

The correct answer is:

B. was cut through by a scalpel

Topic: Plant Structure Drawing

The epicarp is shown with double lines to show that a scalpel was used to cut through the fruit. This is how scientists draw cut sections of fruits to show what is inside them.

Here's why the other answers are wrong:

• A. has been badly drawn with HB pencil: Double lines in scientific drawings have a purpose, not a drawing mistake.


• C. has started rotting and the fruit is spoilt for practical: Rotting fruit would not be shown with clean double lines in a diagram.


• D. was succulent and ripe before plucking: Being ripe would not be shown by double lines in a drawing.

Explanation:

The correct answer is:

B. placentation is axile and section is transverse

Topic: Plant Fruit Structure

The diagram shows seeds attached to a center column inside the fruit. This is called axile placentation. The fruit was cut across its width, which is called a transverse section. This is how oranges and other citrus fruits are built inside.

Here's why the other answers are wrong:

• A. fruit is dispersed by wind: Wind dispersal has nothing to do with how seeds are arranged inside the fruit.


• C. section of fruit is longitudinal and placentation is basal: The cut goes across the fruit (transverse), not lengthwise (longitudinal). The seeds are not at the bottom (basal).


• D. type of fruit is dry indehiscent: This describes how the fruit opens or stays closed, not how the seeds are arranged inside.

Explanation:

The correct answer is:

D. Glucose

Topic: Photosynthesis Process

Glucose is the primary product of photosynthesis. During this process, plants use carbon dioxide, water, and sunlight to produce glucose and oxygen. This glucose serves as an energy source and building block for other organic compounds in the plant.

Here's why the other answers are wrong:

• A. Vitamin: Vitamins are not the main product made during photosynthesis. They are made later using glucose as a building block.


• B. Protein: Proteins are complex molecules that plants make using glucose and other nutrients, but they are not the direct product of photosynthesis.


• C. Lipid: Lipids are fats and oils that plants can make from glucose, but glucose itself is what gets made first in photosynthesis.

Explanation:

The correct answer is:

C. blow air into the jar

Topic: Water Culture Experiments

In water culture experiments, a bent glass tube is used to blow air into the gas jar. This supplies oxygen for root respiration and helps with proper gas exchange. It makes sure that the plant gets enough oxygen for its cellular processes while the roots are in the water solution.

Here's why the other answers are wrong:

• A. stabilize the air inside the jar: The tube is not for stabilizing air but for actively adding fresh air with oxygen to the jar.


• B. provide sunlight for the plant: A glass tube cannot provide sunlight. Sunlight comes from external light sources like the sun or lamps.


• D. prevent entry of microbes into the jar: The tube actually creates an opening that could allow microbes in. Its purpose is air supply, not protection from germs.

Explanation:

The correct answer is:

D. Biuret test

Topic: Food Tests and Chemical Reactions

The Biuret test is used to detect proteins in a solution. It involves adding Biuret reagent to the sample, and a violet or purple color shows the presence of peptide bonds. Unlike other food tests, the Biuret test does not require heating to show a positive result.

Here's why the other answers are wrong:

• A. Benedict's test: This test detects reducing sugars but requires heating in a water bath to work properly and show the color change.


• B. Fehling's test: This test also detects reducing sugars and needs heating to produce the brick-red precipitate that shows a positive result.


• C. Millon's test: This test detects proteins containing tyrosine and requires heating to develop the red color that indicates a positive result.

Explanation:

The correct answer is:

B. Herbivorous animals

Topic: Animal Teeth and Feeding Habits

The part labeled II shows the diastema, which is a gap between the front teeth (incisors) and the back teeth (molars and premolars). This gap is a special feature found in herbivorous animals. The diastema gives space for the tongue to move food around while chewing tough plant materials.

Here's why the other answers are wrong:

• A. Carnivorous animals: These animals eat meat and have sharp pointed teeth with no gaps. They need their teeth close together to tear flesh.


• C. Omnivorous animals: These animals eat both plants and meat. They have mixed tooth types but do not have the large gap (diastema) like herbivores.


• D. Holozoic animals: This term means animals that eat solid food, which includes carnivores, herbivores, and omnivores. It does not describe the specific tooth gap feature.

Explanation:

The correct answer is:

B. It allows the tongue to roll food

Topic: Function of Diastema in Herbivores

The diastema (part II) is a gap that gives the tongue space to move and roll plant food around in the mouth. This helps herbivorous animals move tough plant materials to their grinding teeth (molars) so they can chew their food properly before swallowing.

Here's why the other answers are wrong:

• A. It represents the absence of canine: While herbivores may have small or no canine teeth, the diastema is not just about missing teeth. It is an active space that helps with food processing.


• C. It is used by carnivores for removing flesh: Carnivores do not have a diastema. They have sharp teeth close together to tear meat, not gaps for tongue movement.


• D. For effective grinding of bones: The diastema does not grind anything. The molars at the back of the mouth do the grinding work.

Explanation:

The correct answer is:

C. Incisor

Topic: Types of Teeth in Mammals

The part labeled I points to the incisors. These are the front teeth that have a flat, sharp edge like a chisel. Incisors are used for cutting and biting food. In herbivorous animals, the incisors help cut and grab plant materials before moving them back to the grinding teeth.

Here's why the other answers are wrong:

• A. Molar: Molars are the large flat teeth at the very back of the mouth used for grinding food. They are not at the front where part I is pointing.


• B. Premolar: Premolars are the teeth between the canines and molars. They help with grinding but are located in the middle of the tooth row, not at the front.


• D. Canine: Canine teeth are the pointed teeth next to the incisors. In this herbivore skull, the canines are very small or missing, and part I is pointing to the flat cutting teeth at the very front.

Explanation:

The correct answer is:

D. Swarming

Topic: Animal Survival Strategies

Swarming is a social behavior where animals like bees or locusts move in large groups. It is not mainly used to survive unfavorable conditions. Instead, it is used for reproduction, finding new homes, or protection from predators.

Here's why the other answers are wrong:

• A. Migration: This is when animals move from one place to another to escape cold weather, find food, or avoid harsh conditions during certain seasons.


• B. Hibernation: This is when animals go into a deep sleep during winter to survive cold temperatures and lack of food by slowing down their body processes.


• C. Aestivation: This is when animals go into a dormant state during hot, dry periods to survive extreme heat and drought conditions.

Explanation:

The correct answer is:

D. young trees gradually build up to form forest cover

Topic: Environmental Impact of Bushfires

Bushfires destroy vegetation, including young trees, rather than helping them grow. The gradual build-up of forest cover happens through natural forest growth and tree planting programs, not through bushfires. Bushfires actually cause the opposite effect by destroying existing forest cover.

Here's why the other answers are wrong:

• A. strong winds result from destroyed wind breaks: This is a real consequence of bushfires. When trees that act as windbreaks are burned down, the area becomes more exposed to strong winds.


• B. timber from forests are destroyed: This is a direct consequence of bushfires. The fires burn and destroy valuable timber trees, causing economic losses to the forestry industry.


• C. fertile soil is lost as humus is burnt off: This is a major consequence of bushfires. When organic matter in the soil burns, it reduces soil fertility and makes it harder for plants to grow back.

Explanation:

The correct answer is:

A. grass

Topic: Energy Flow in Food Chains

In a food chain, energy decreases as you move from producers to higher levels. Grass is a producer that directly captures solar energy through photosynthesis, so it has the highest percentage of energy. Only about 10% of energy is transferred to each next level, meaning consumers like goats and lions get much less energy.

Here's why the other answers are wrong:

• B. goat: The goat is a primary consumer that eats grass. It only receives about 10% of the energy that was in the grass, so it has much less energy than the producer.


• C. lion: The lion is a secondary consumer that eats goats. It receives only about 1% of the original energy from grass, making it the organism with the least energy in this food chain.


• D. mushroom: Mushrooms are decomposers that break down dead organic matter. They get energy from waste and dead organisms, which contains very little energy compared to living producers.

Explanation:

The correct answer is:

D. Abyssal zone

Topic: Marine Habitat Zones

The abyssal zone is the deepest part of the ocean and receives little to no sunlight. It is cold, dark, and under high pressure, with specialized organisms that have adapted to survive in these harsh conditions without light.

Here's why the other answers are wrong:

• A. Littoral zone: This is the shallow water area near the shore where light easily reaches the bottom, supporting many plants and algae that need sunlight.


• B. Euphotic zone: This is the upper layer of the ocean where there is enough light for photosynthesis to occur. It actually receives the most light of all ocean zones.


• C. Splash zone: This is the area above the high tide line that gets splashed by waves. It receives direct sunlight and is not even underwater most of the time.

Explanation:

The correct answer is:

C. recycle mineral nutrients

Topic: Role of Decomposers in Ecosystems

Decomposers like bacteria and fungi break down dead organisms and waste products. This process releases mineral nutrients back into the soil, making them available for plants to use again. Decomposers play a critical role in nutrient cycling and keeping the ecosystem balanced.

Here's why the other answers are wrong:

• A. accumulate waste products: Decomposers do not store or pile up waste. Instead, they break down waste and dead matter to release nutrients back into the environment.


• B. provide energy for consumers: Decomposers do not directly give energy to consumers like animals. Consumers get energy by eating producers or other consumers, not decomposers.


• D. provide energy for producers: Decomposers do not give energy to plants. Plants get their energy from sunlight through photosynthesis, not from decomposers.

Explanation:

The correct answer is:

B. Flower stalk is long to reach pollinators

Topic: Plant Adaptations in Aquatic Environments

The part labeled X is the flower stalk. Its long length is an adaptation that allows the flower to reach the surface of the water. This helps the flower connect with pollinators like insects that fly above the water or land on the water surface.

Here's why the other answers are wrong:

• A. Stem is long for growth: The labeled part X is specifically the flower stalk, not the main stem. Growth is not the main purpose of this adaptation.


• C. Flowers are numerous for pollination: This answer talks about the number of flowers, but the question asks about the adaptation of part X, which is the long flower stalk.


• D. Flowers and leaves are on the same level to get sunlight: The flowers are actually above the leaves in this plant. The main purpose of the long stalk is to reach pollinators, not sunlight.

Explanation:

The correct answer is:

B. lily

Topic: Identification of Aquatic Plants

The plant shown has broad, flat leaves that float on water and large flowers that bloom at the water surface. These features are typical of a water lily.

Here's why the other answers are wrong:

• A. lettuce: Water lettuce has small, fuzzy leaves arranged in a circle shape. It does not have large flowers like the one shown in the picture.


• C. fern: Water ferns have divided leaves that look like feathers. They do not have large flowers because ferns reproduce using spores, not flowers.


• D. hornwort: Hornwort is a plant that grows completely underwater with thin, needle-like leaves. It does not have floating leaves or large flowers.

Explanation:

The correct answer is:

C. Pooter

Topic: Scientific Instruments for Insect Collection

A pooter is a simple tool used by scientists to collect small insects by suction. It has a jar with two tubes - one for sucking air and another for drawing in insects. It works well for collecting insects from soil litter and crevices without harming them.

Here's why the other answers are wrong:

• A. Anemometer: This tool measures wind speed and direction, not for collecting insects.


• B. Barometer: This tool measures air pressure in weather studies, not for collecting insects.


• D. Quadrat: This is a square frame used to mark areas for counting plants or animals, not for collecting insects.

Explanation:

The correct answer is:

D. Malaria

Topic: Disease Vectors and Transmission

Houseflies are mechanical vectors that carry germs on their bodies, legs, and mouth parts. They spread diseases by landing on dirty things and then on food or surfaces that people touch.

Malaria is different because it is only spread by female Anopheles mosquitoes, not houseflies. The malaria parasite must grow inside the mosquito before it can infect people.

Here's why the other answers are wrong:

• A. Typhoid: Houseflies do spread typhoid by carrying the bacteria from waste to food and water.


• B. Dysentery: Houseflies do spread dysentery by carrying the germs from dirty places to clean areas.


• C. Cholera: Houseflies do spread cholera by moving the bacteria from contaminated areas to food and water.

Explanation:

The correct answer is:

B. Conserving more water

Topic: Water Conservation in Reptiles

Agama lizards excrete uric acid as a thick paste or solid instead of liquid urine. This saves a lot of water because very little water is needed to remove the waste. This helps the lizard survive in hot, dry places where water is hard to find.

Here's why the other answers are wrong:

• A. Excreting more water: This is the opposite of what happens. Uric acid helps the lizard lose less water, not more water.


• C. Living on land: While lizards do live on land, many land animals use different waste removal methods. Uric acid is specifically for saving water.


• D. Laying shelled eggs: This is a separate adaptation. Uric acid excretion is about saving water, not about egg laying.

Explanation:

The correct answer is:

A. Extinction of animals

Topic: Conservation and Ecosystem Balance

When rare animal species are killed, they can become extinct because there are already very few of them left. Once a species goes extinct, it is gone forever and can never come back. This hurts the ecosystem because every animal has a job to do in nature, like controlling other animal populations or spreading seeds.

Here's why the other answers are wrong:

• B. Availability of meat for the people: This might happen in the short term, but it is not a consequence to the ecosystem. The question asks about effects on the ecosystem, not benefits to humans.


• C. Reduction in the number of predators: This could happen if the rare species being killed are predators, but not all rare species are predators. This is too specific and not the main consequence.


• D. Outbreak of diseases: While this could happen in some cases, it is not the direct consequence of killing rare species. The main problem is extinction.

Explanation:

The correct answer is:

C. I, III, and IV

Topic: Natural Resource Conservation Methods

Conservation means protecting and using natural resources wisely so they last longer. Let's look at each statement:

• Statement I - Turning off taps saves water, which is conservation.
• Statement III - Letting farmland rest (fallow) lets the soil get nutrients back, which conserves soil.
• Statement IV - Helping rare animals have babies increases their numbers, which conserves wildlife.
• Statement II - Burning bushes destroys plants and habitat, which is harmful, not conservation.

Here's why the other answers are wrong:

• A. I, II, and III: This includes statement II (burning bushes), which harms the environment instead of conserving it.


• B. I, II and IV: This includes statement II (burning bushes), which destroys habitat and plants.


• D. II, III, and IV: This includes statement II (burning bushes), which is destructive, not conservation.

Explanation:

The correct answer is:

C. Wildlife

Topic: Biological Cycles in Conservation

A biological cycle means using living processes like reproduction, growth, and development. In the statements, only wildlife conservation uses biological cycles - making rare animals reproduce involves mating, pregnancy, and birth, which are all biological processes.

Here's why the other answers are wrong:

• A. Water: Turning off taps is a physical action, not a biological cycle. It just stops water from flowing out.


• B. Soil: Letting farmland rest (fallow) is a physical process where we just stop using the land. The soil recovers naturally but we don't use biological cycles to help it.


• D. Forest: Forest is not mentioned in any of the four statements given in the question.

Explanation:

The correct answer is:

A. blood group

Topic: Types of Variation in Biology

Blood group is an example of discontinuous variation because it has clear and separate categories. People can only have blood type A, B, AB, or O. There are no blood types in between these groups.

Here's why the other answers are wrong:

• B. skin colour: This shows continuous variation because skin colour ranges from very light to very dark with many shades in between.


• C. shape: This shows continuous variation because body shapes can vary gradually from thin to wide with many sizes in between.


• D. height: This shows continuous variation because people can be any height within a range, not just tall or short categories.

Explanation:

The correct answer is:

C. b

Topic: Blood Groups and Antibodies

People with blood group A have A antigens on their red blood cells. Their body makes antibodies against the opposite type, which is anti-B antibodies (also called b antibodies). This protects them from receiving the wrong blood type.

Here's why the other answers are wrong:

• A. a and b: People with blood group A cannot have both a and b antibodies. They only make antibodies against what they don't have.


• B. a: People with blood group A do not make anti-A antibodies because that would attack their own blood cells.


• D. o: There is no such thing as anti-O antibodies in the ABO blood group system.

Explanation:

The correct answer is:

C. AO, AA and OO

Topic: Blood Transfusion Compatibility

A person with blood group A can safely receive blood from donors with blood group A (both AA and AO genotypes) and blood group O (OO genotype). This is because their anti-B antibodies will not attack A antigens or the absence of antigens in O blood.

Here's why the other answers are wrong:

• A. AO and AB: AB blood contains B antigens which would be attacked by the anti-B antibodies in blood group A patients, causing a dangerous reaction.


• B. AO and BO: BO blood produces B antigens which would be attacked by the anti-B antibodies in blood group A patients.


• D. AB, AO and OO: AB blood contains B antigens which are not compatible with blood group A patients who have anti-B antibodies.

Explanation:

The correct answer is:

D. mutation

Topic: DNA Structure Changes

A mutation is a direct change in the DNA sequence of an organism. This change can happen because of environmental factors like radiation or chemicals, or it can occur naturally when DNA copies itself. Mutations actually alter the molecular structure of DNA by changing the order of its building blocks.

Here's why the other answers are wrong:

• A. variation: This describes the differences we see between organisms, but it does not cause changes to DNA structure itself.


• B. evolution: This is the long-term process of species changing over time, but it does not directly change DNA structure in individual organisms.


• C. heredity: This is the passing of traits from parents to children through existing DNA, but it does not change the DNA structure.

Explanation:

The correct answer is:

D. independent assortment of genes

Topic: Mendel's Laws of Inheritance

Mendel's second law is called the Law of Independent Assortment. This law says that different pairs of genes are passed to children independently of each other. For example, the gene for seed shape is passed down separately from the gene for seed color. This happens when genes are located on different chromosomes.

Here's why the other answers are wrong:

• A. dependent segregation of genes: This uses the word "dependent" which is wrong because genes assort independently, and "segregation" refers to Mendel's first law, not the second.


• B. dependent assortment of genes: This uses the word "dependent" which is incorrect because the law specifically states that genes assort independently of each other.


• C. independent segregation of genes: This mixes up the terms - "segregation" refers to Mendel's first law, while the second law is about "assortment".

Explanation:

The correct answer is:

C. phenotype

Topic: Genetics Terms

Phenotype is the physical or observable characteristic of an organism that you can actually see or measure, such as eye color, height, or blood type. It is what the genes actually produce when they are expressed in the body and affected by the environment.

Here's why the other answers are wrong:

• A. genotype: This is the genetic makeup or DNA code that an organism carries, but it is not observable. You cannot see genotype just by looking at someone.


• B. variation: This refers to the differences that exist between individuals in a species, but it is not the term for observable traits themselves.


• D. hybrid: This refers to an organism that comes from crossing two different genetic types, but it is not the term for observable expression of traits.

Explanation:

The correct answer is:

D. three smooth, one wrinkled

Topic: Genetics - Phenotype from Genotype

The offspring genotypes are SS, Ss, Ss, and ss. Since S is the dominant allele for smooth and s is the recessive allele for wrinkled, any genotype with at least one S will show the smooth phenotype. Only ss will show the wrinkled phenotype because it has no dominant allele.

Here's why the other answers are wrong:

• A. one smooth, one wrinkled: This count is too low because three genotypes (SS, Ss, Ss) will all show smooth phenotype, not just one.


• B. one smooth, three wrinkled: This reverses the count because dominant alleles are more common in the phenotype than recessive ones in this cross.


• C. two smooth, two wrinkled: This count is wrong because both Ss genotypes will show smooth phenotype due to dominance, making three smooth total.

Explanation:

The correct answer is:

C. Ss and Ss

Topic: Genetics - Parent Genotypes from Offspring

The F1 offspring show the pattern SS, Ss, Ss, and ss, which is the classic 1:2:1 genotype ratio. This pattern only happens when two heterozygous parents (both Ss) are crossed together. Each parent contributes either S or s, creating all possible combinations.

Here's why the other answers are wrong:

• A. SS and ss: This cross would only produce Ss offspring, not the mix of SS, Ss, and ss that we see.


• B. SS and Ss: This cross would produce only SS and Ss offspring, but no ss offspring which we need to match our results.


• D. Ss and ss: This cross would produce only Ss and ss offspring, but no SS offspring which we need to match our results.

Explanation:

The correct answer is:

D. the uniformity of embryonic stages of vertebrates

Topic: Evidence for Evolution

The similarity in embryonic development stages across different vertebrates is strong evidence that all these animals evolved from a common ancestor. For example, the embryos of fish, birds, and mammals all show similar features like gill slits and tails in their early stages, even though adults look very different.

Here's why the other answers are wrong:

• A. the extinction of horses: Horses are not extinct and their extinction would not provide evidence for evolution. Evolution is about how species change over time, not about them disappearing.


• B. increase in the weight of boys: This is not evolutionary change but rather changes in nutrition and lifestyle that happen within a single generation, not over many generations.


• C. studying the behaviour of members in a family: Family behavior studies show learned behaviors and immediate genetic traits, but not the long-term changes that demonstrate evolution.

Explanation:

The correct answer is:

A. natural selection

Topic: Mechanisms of Evolution

Natural selection is the way nature keeps the good changes in animals and plants. Animals with good traits live longer and have more babies. Animals with bad traits die more often and have fewer babies. Over time, this keeps all the good changes that make animals better at surviving.

Here's why the other answers are wrong:

• B. isolation: This means keeping groups of animals apart from each other, but it does not keep good changes - it just separates animals.


• C. speciation: This is what happens when one type of animal becomes two different types, but it is not what keeps good changes in animals.


• D. conservation of life: This means protecting animals from dying out completely, but it is not the natural way that keeps good changes in animals.

Explanation:

The correct answer is:

A. Jean Lamarck

Topic: Early Ideas About Evolution

Jean Lamarck came up with the idea that animals grow new body parts when they need them and lose body parts they do not use. For example, he thought giraffes got long necks because they kept stretching to eat leaves high up in trees. This idea is called the theory of use and disuse.

Here's why the other answers are wrong:

• B. Charles Darwin: He came up with the idea of natural selection, which says animals with good traits survive better, not that they grow new parts when they need them.


• C. Gregor Mendel: He studied how traits pass from parents to children through genes, not how new body parts develop when needed.


• D. Louis Pasteur: He studied germs and diseases, not how animals change or grow new body parts over time.