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IGCSE Biology Mock – Set 2 Paper 3-Updated 2026

IGCSE Biology Mock – Set 2 Paper 3 – Updated 2026

Preparing for your CIE IGCSE Biology exam can be daunting, but with the right approach, you can achieve your goals with CIE iGCSE Biology Mock test.

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iGCSE Practice Questions, Past Papers, Flashcards and notes available for iGCSE Students at IITian Academy.

CIE iGCSE Biology Mock test – All Sets

Question 

(a) Fig. 3.1 shows blood flow through a human heart.
The arrows show the direction of blood flow.
(i) On Fig. 3.1, draw a label line and the letter X to identify the muscular wall of the left ventricle.
(ii) Describe the path taken by blood as it moves from A to B in Fig. 3.1.
(iii) State the name of blood vessel C shown in Fig. 3.1. 
(b) The activity of the heart can be monitored using an ECG.
Fig. 3.2 shows the results of an ECG for a person who has been resting for 15 minutes.

(i) Fig. 3.3 shows the results of ECGs for the same person:

  • resting
  • during vigorous physical activity
  • one minute after physical activity
  • one hour after physical activity.

Draw lines to link each activity with its ECG. Draw three lines.
One has been done for you.

(ii) State two other ways that the activity of the heart can be monitored.
(c) During vigorous physical activity humans respire anaerobically.
(i) Tick (✓) three statements that describe anaerobic respiration in humans.
(ii) State how vigorous exercise affects the rate and depth of breathing.

Most-appropriate topic codes (Syllabus 0610):

• TOPIC 9.2: Heart — parts (a), (b)
• TOPIC 12.3: Anaerobic respiration — part (c)(i)
• TOPIC 11.1: Gas exchange in humans — part (c)(ii)
▶️ Answer/Explanation
Detailed solution

(a) (i)
The label line X must point to the thick muscular wall of the left ventricle. (Note: The left ventricle is on the right side of the diagram, characterised by a thicker wall compared to the right ventricle).

(a) (ii)
The path of blood from A (Vena Cava) to B (Pulmonary Artery) is as follows:

  • Blood enters the right atrium from A.
  • It moves into the right ventricle.
  • It passes through a valve (specifically the tricuspid valve into the ventricle, or the semilunar valve out of the ventricle) to exit via B.

(a) (iii)
Pulmonary vein. (This vessel carries oxygenated blood from the lungs back to the left atrium).

(b) (i)


Matching the activity to the ECG trace:

  • Resting: Top graph (Normal/slow rhythm) — (Already matched in question).
  • During vigorous physical activity: 2nd graph down (The peaks are closest together, indicating the fastest heart rate).
  • One minute after physical activity: 3rd graph down (The heart rate is slowing down but is still faster than resting).
  • One hour after physical activity: Bottom graph (The heart rate has returned to the resting rate).

(b) (ii)
Any two of the following:

  • Counting the pulse rate.
  • Listening to the sound of the valves (using a stethoscope).
  • Measuring blood pressure (AVP).

(c) (i)
The correct statements for anaerobic respiration in humans are:

Note: Alcohol and carbon dioxide are produced during anaerobic respiration in yeast (fermentation), not humans.

(c) (ii)
Vigorous exercise causes an:

  • Increase in the rate of breathing.
  • Increase in the depth of breathing.
IGCSE Biology Mock Paper 3 - Full Access
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