A LEVEL BIOLOGY A (SNAB): PAST PAPER 1
& GRADING GUIDE THE NATURAL
ENVIRONMENT AND SPECIES SURVIVAL
ALL ASSESSMENT & LEVEL-BY-LEVEL
MARK SCHEME CERTIFICATION SCRIPT
2026 QUESTIONS WITH SOLUTIONS
GRADED A+
◍ - rare / random;- change in gene / allele / genome / DNA / genetic code / eq.
Answer: Explain what is meant by the term mutation. [2]
◍ 1. less gas exchange / less diffusion; 2. less surface area;3. increased
distance;4. (less) oxygen into blood;5. (less) (aerobic) respiration;6.
anaerobic respiration / lactic acid / oxygen debt; 7. (less) energy / ATP for
muscles;.
Answer: Suggest why pneumoconiosis reduces the ability of a person to
exercise. [5]
◍ 1. natural selection;2. variation / varied / vary in shape / colour;3. mutation /
mutated;4. not seen by predators / not eaten / camouflaged / not attacked /
eq;5. survive / survival / survival (of the fittest); 6. reproduce / produce
offspring / eq;7. pass on allele / gene / DNA;.
Answer: Explain how katydids have evolved to look like leaves. [5]
◍ Who was a student of Plato that modified his organization of nature?.
Answer: Aristotle
◍ What conditions are necessary for fossilization to occur?.
, Answer: Water, pressure, and a lot of time.
◍ - link between pollen number and symptoms / eq- Person A allergic to tree
pollen (only)- Person B allergic to (mainly) grass pollen- Person B some /
mild allergy to tree and weed- Person C allergic to all pollen / tree and grass
and weed- Person D no pollen allergy- Person E allergic to (mainly) grass
and weed- Person E some / mild allergy to tree- no species level data- only
one year.
Answer: Using the data in the table and the information from the graph,
discuss the likely causes of the allergic responses in each person. [5]
◍ May increase yield of milk or meat for farmers.May increase profit.May be
able to improve nutritional value of a food.But increases risk of inheriting
genetic diseases.Cost of selective breeding may outweigh benefit.Some
consider practice of selective breeding cruel and unethical..
Answer: Evaluate the various benefits and drawbacks of using selective
breeding in livestock animals. [4]
◍ 1. reduce growth;2. damage leaves / fewer leaves / less surface area / eq;3.
(less) light absorbed;4. (less) photosynthesis;5. (less) starch / glucose /
carbohydrate / amino acids / eq;6. infection / disease / entry of pathogens /
bacteria / viruses;.
Answer: Explain how katydids affect the growth of the plants they feed on.
[4]
◍ - (more) light into eye / retina- to see danger / be more aware of
surroundings- more blood to lungs- more blood to (leg) muscles / blood
diverted to (leg) muscles- more oxygen (to muscles)- more glucose (to
muscles / in blood)- more respiration / less anaerobic respiration / less lactic
acid produced- more ATP / energy- run faster / escape / contract muscles
more / eq.
Answer: Adrenaline is released into the blood when there is danger.The list
gives the effects of adrenaline on different parts of the body.• dilates the
pupil in the eye• increases heart rate• narrows small arteries in the intestine•
converts glycogen into glucose in the liverExplain the advantages of these
, effects to a person in danger [5]
◍ - increases (steeply) up to 20-25 years- levels off / peaks 20-25 years-
decreases (steadily at constant rate) from 20-25 years.
Answer: Vital capacity is the maximum volume of air that a person can
force out of their lungs in one breath.Describe the relationship between vital
capacity and age shown by the graph. [2]
◍ An explanation that makes reference to 4 of the following points.• variation
in amount of body hair / eq (1)• caused by mutation (1)• less hair increased
heat loss / can lose heat in sun / warm / hot climate / chase animals / started
to wear clothes / eq (1)• survive and reproduce (1)• pass on alleles / genes to
offspring (1).
Answer: Modern humans have less body hair than their ancestors.Explain
how this evolutionary change was brought about by natural selection.
◍ Remember to use these key words:• survives• less competition• mutation•
reproduce• pass allele / gene / DNA on to offspring.
Answer: NATURAL SELECTION QUESTION!!
◍ - more energy transferred / less energy lost / less heat loss / less movement
in aquatic / more of producer eaten / not all crop eaten.
Answer: Suggest why the biomass transfer is different in the coral reef
compared to the crop field. [1]
◍ What happens to organisms that die in water and settle at the bottom?.
Answer: They can be covered by layers of sediment, leading to fossilization.
◍ What is a subcategory of species?.
Answer: Breeds
◍ An answer that makes reference to two of the following points:- circular
muscles contract- radial muscles relax- pupil constricts.
Answer: Explain how the iris controls the diameter of the pupil in bright
light. [3]
◍ - W or stigma / feathery / large surface area / stigma outside flower /
& GRADING GUIDE THE NATURAL
ENVIRONMENT AND SPECIES SURVIVAL
ALL ASSESSMENT & LEVEL-BY-LEVEL
MARK SCHEME CERTIFICATION SCRIPT
2026 QUESTIONS WITH SOLUTIONS
GRADED A+
◍ - rare / random;- change in gene / allele / genome / DNA / genetic code / eq.
Answer: Explain what is meant by the term mutation. [2]
◍ 1. less gas exchange / less diffusion; 2. less surface area;3. increased
distance;4. (less) oxygen into blood;5. (less) (aerobic) respiration;6.
anaerobic respiration / lactic acid / oxygen debt; 7. (less) energy / ATP for
muscles;.
Answer: Suggest why pneumoconiosis reduces the ability of a person to
exercise. [5]
◍ 1. natural selection;2. variation / varied / vary in shape / colour;3. mutation /
mutated;4. not seen by predators / not eaten / camouflaged / not attacked /
eq;5. survive / survival / survival (of the fittest); 6. reproduce / produce
offspring / eq;7. pass on allele / gene / DNA;.
Answer: Explain how katydids have evolved to look like leaves. [5]
◍ Who was a student of Plato that modified his organization of nature?.
Answer: Aristotle
◍ What conditions are necessary for fossilization to occur?.
, Answer: Water, pressure, and a lot of time.
◍ - link between pollen number and symptoms / eq- Person A allergic to tree
pollen (only)- Person B allergic to (mainly) grass pollen- Person B some /
mild allergy to tree and weed- Person C allergic to all pollen / tree and grass
and weed- Person D no pollen allergy- Person E allergic to (mainly) grass
and weed- Person E some / mild allergy to tree- no species level data- only
one year.
Answer: Using the data in the table and the information from the graph,
discuss the likely causes of the allergic responses in each person. [5]
◍ May increase yield of milk or meat for farmers.May increase profit.May be
able to improve nutritional value of a food.But increases risk of inheriting
genetic diseases.Cost of selective breeding may outweigh benefit.Some
consider practice of selective breeding cruel and unethical..
Answer: Evaluate the various benefits and drawbacks of using selective
breeding in livestock animals. [4]
◍ 1. reduce growth;2. damage leaves / fewer leaves / less surface area / eq;3.
(less) light absorbed;4. (less) photosynthesis;5. (less) starch / glucose /
carbohydrate / amino acids / eq;6. infection / disease / entry of pathogens /
bacteria / viruses;.
Answer: Explain how katydids affect the growth of the plants they feed on.
[4]
◍ - (more) light into eye / retina- to see danger / be more aware of
surroundings- more blood to lungs- more blood to (leg) muscles / blood
diverted to (leg) muscles- more oxygen (to muscles)- more glucose (to
muscles / in blood)- more respiration / less anaerobic respiration / less lactic
acid produced- more ATP / energy- run faster / escape / contract muscles
more / eq.
Answer: Adrenaline is released into the blood when there is danger.The list
gives the effects of adrenaline on different parts of the body.• dilates the
pupil in the eye• increases heart rate• narrows small arteries in the intestine•
converts glycogen into glucose in the liverExplain the advantages of these
, effects to a person in danger [5]
◍ - increases (steeply) up to 20-25 years- levels off / peaks 20-25 years-
decreases (steadily at constant rate) from 20-25 years.
Answer: Vital capacity is the maximum volume of air that a person can
force out of their lungs in one breath.Describe the relationship between vital
capacity and age shown by the graph. [2]
◍ An explanation that makes reference to 4 of the following points.• variation
in amount of body hair / eq (1)• caused by mutation (1)• less hair increased
heat loss / can lose heat in sun / warm / hot climate / chase animals / started
to wear clothes / eq (1)• survive and reproduce (1)• pass on alleles / genes to
offspring (1).
Answer: Modern humans have less body hair than their ancestors.Explain
how this evolutionary change was brought about by natural selection.
◍ Remember to use these key words:• survives• less competition• mutation•
reproduce• pass allele / gene / DNA on to offspring.
Answer: NATURAL SELECTION QUESTION!!
◍ - more energy transferred / less energy lost / less heat loss / less movement
in aquatic / more of producer eaten / not all crop eaten.
Answer: Suggest why the biomass transfer is different in the coral reef
compared to the crop field. [1]
◍ What happens to organisms that die in water and settle at the bottom?.
Answer: They can be covered by layers of sediment, leading to fossilization.
◍ What is a subcategory of species?.
Answer: Breeds
◍ An answer that makes reference to two of the following points:- circular
muscles contract- radial muscles relax- pupil constricts.
Answer: Explain how the iris controls the diameter of the pupil in bright
light. [3]
◍ - W or stigma / feathery / large surface area / stigma outside flower /
