AQA GCSE Combined Science: Trilogy Biology Paper 1 (Foundation), 2020: Question 1

💡 Key knowledge for the whole question

• Healthy weight can be affected by diet and exercise.
• Exercise has long-term health benefits beyond weight loss.
• Aerobic respiration: glucose + oxygen → carbon dioxide + water.
• Gas exchange happens in the alveoli in the lungs.
• Fitter people often have lower resting breathing rates and recover faster after exercise.
• Anaerobic respiration in muscles happens when there is not enough oxygen and produces lactic acid.

🧠 Exam technique for the whole question

• If the question says do not refer to weight loss, do not mention it.
• For data questions, make comparisons using the table.
• For multiple-choice items, read all options carefully before choosing.
• For 2-mark questions, give two separate points.
• Use exact biology terms like alveoli , oxygen , lactic acid .

✅ Correct answer

Eat less fatty food

💡 Key knowledge

Fatty foods can be high in energy. Eating less of them can help reduce energy intake and help with body mass loss.

❌ Common errors

• Choosing drink more alcohol — this would not help.
• Choosing stop smoking — good for health, but not the mark scheme answer for body mass loss here.

✅ Correct answers

Any two from:

• strengthens muscles
• strengthens the heart
• reduces risk of coronary heart disease / cardiovascular disease
• reduces blood pressure
• reduces risk of Type 2 diabetes
• improves mental health / mood
• improves mobility

🧠 Exam technique

This is a classic “name two” question. Keep answers short and clear.

Model full-mark answer:

1. Exercise strengthens the heart.
2. Exercise reduces the risk of Type 2 diabetes.

❌ Common errors

• Mentioning losing weight / body mass — the mark scheme says ignore this.
• Giving immediate effects like increases heart rate — not accepted here.
• Saying only it makes you healthier — too vague.
• Saying improves appearance — not credited.

💡 Examiner insight

Students lost marks by giving vague statements instead of specific health benefits. Top answers named clear biological benefits such as reducing blood pressure or strengthening the heart.

✅ Correct answer

glucose + oxygen → carbon dioxide + water

💡 Key knowledge

Aerobic respiration releases energy from glucose using oxygen.

❌ Common errors

• Reversing the equation.
• Putting carbon dioxide and water on the left-hand side.
• Confusing aerobic respiration with photosynthesis.

✅ Correct answer

C

💡 Key knowledge

Gas exchange takes place in the alveoli, the tiny air sacs in the lungs. Oxygen diffuses into the blood and carbon dioxide diffuses out.

🧠 Exam technique

On breathing-system diagrams, look for the small grape-like sacs at the ends of the bronchioles. That is where gas exchange happens.

✅ Correct answers

Any two comparative points from Table 1:

• B had the lowest resting breathing rate (10 breaths per minute).
• B had the lowest breathing rate after exercise (28 breaths per minute).
• B had the lowest increase in breathing rate (18 breaths per minute).
• B took the least time to return to resting rate / shortest recovery time (4.0 minutes).

🧠 Exam technique

The mark scheme says answers must be comparative. That means do not just say what B’s result was — compare it with the others.

Model full-mark answer:

1. Person B had the lowest resting breathing rate of all four people.
2. Person B also had the shortest time to return to the resting rate after exercise.

📐 Using the table clearly

• A recovery time = 5.5 min
• B recovery time = 4.0 min
• C recovery time = 6.5 min
• D recovery time = 10.0 min

So B recovered fastest.

❌ Common errors

• Not comparing B to the others.
• Only giving one reason.
• Saying B is fittest just because B has a low breathing rate, without linking it to being the lowest.

✅ Correct answers

Any two from:

• It was only based on one measurement.
• Person B may have done less intense exercise.
• Other factors besides breathing rate indicate fitness.

💡 Examiner insight

This is about evaluating a method and conclusion. Better answers focused on fairness and reliability. The mark scheme also allows the idea that a different type of exercise may have been done.

🧠 Exam technique

For “may not be valid”, think about:

• Was the test repeated?
• Was it fair for everyone?
• Does one measurement prove the conclusion?

❌ Common errors

• Talking about medical conditions — the mark scheme says ignore these.
• Giving vague answers like it might be wrong.
• Forgetting that fitness can involve stamina, strength and speed, not just breathing rate.

✅ Correct answers

• deeper breathing
• increased heart rate

💡 Key knowledge

During aerobic exercise, the body needs more oxygen and more glucose for respiration, so the heart works faster and breathing becomes deeper.

🧠 Exam technique

The question says do not refer to increased breathing rate. So say deeper breathing, not faster breathing.

❌ Common errors

• Breathing rate increases — specifically not allowed.
• More blood flows around body — too vague.
• Lactic acid is produced — not accepted here.

✅ Correct answers

Muscles respire anaerobically if they do not have enough oxygen.

Anaerobic respiration of glucose produces lactic acid.

💡 Key knowledge

During vigorous exercise, oxygen supply may not meet demand. Then muscles use anaerobic respiration, which produces lactic acid.

❌ Common errors

• Choosing carbon dioxide instead of oxygen.
• Choosing glucose as the product instead of lactic acid.
• Mixing up aerobic and anaerobic respiration.

💡 Answers in order

1. Eat less fatty food
2. Any two valid benefits of exercise
3. glucose + oxygen → carbon dioxide + water
4. C
5. Any two comparative reasons from the table for B
6. Any two reasons the conclusion may not be valid
7. deeper breathing; increased heart rate
8. oxygen; lactic acid

🧠 What separated top answers?

• They followed instructions exactly.
• They avoided banned ideas like weight loss in 01.2 and increased breathing rate in 01.7.
• They used comparative data properly in 01.5.
• They evaluated the method sensibly in 01.6, focusing on fairness and reliability.