Home / iGCSE Biology (0610)-9.1 Circulatory systems – iGCSE Style Questions Paper 2

iGCSE Biology (0610)-9.1 Circulatory systems – iGCSE Style Questions Paper 2

IGCSE Biology (0610) Practice Questions Paper 2 - All Chapters

Question

Which statement describes a double circulatory system?

(A) Blood goes through the lungs twice every time it goes round the body.
(B) Blood goes through the kidneys twice every time it goes round the body.
(C) Blood goes through the heart twice every time it goes round the body.
(D) Blood goes through the brain twice every time it goes round the body.
▶️ Answer/Explanation
A double circulatory system consists of two separate circuits: the pulmonary circulation and the systemic circulation. In this system, blood passes through the heart twice for every one complete circuit of the body. First, deoxygenated blood is pumped to the lungs to be oxygenated and returns to the heart. Second, this oxygenated blood is pumped out to the rest of the body before returning to the heart again. This ensures that oxygenated blood is delivered to tissues at a higher pressure than in a single circulatory system.
✅ Answer: (C)

Question

In a fish, what is the sequence of structures that blood passes through after it leaves the heart?

(A) gills $\rightarrow$ muscles $\rightarrow$ heart
(B) gills $\rightarrow$ heart $\rightarrow$ muscles $\rightarrow$ heart
(C) muscles $\rightarrow$ gills $\rightarrow$ heart
(D) muscles $\rightarrow$ heart
▶️ Answer/Explanation

Fish possess a single circulatory system, meaning blood passes through the heart only once during a complete circuit. Deoxygenated blood is pumped from the heart directly to the gills to pick up oxygen and release carbon dioxide. From the gills, the now-oxygenated blood travels straight to the rest of the body, including the muscles, to deliver nutrients and oxygen. Finally, the deoxygenated blood returns to the heart to begin the cycle again. This makes the sequence: Heart $\rightarrow$ Gills $\rightarrow$ Muscles $\rightarrow$ Heart.

✅ Answer: (A)

Question

What is an advantage of a double circulatory system?

(A) It allows the mixing of oxygenated and deoxygenated blood.
(B) It can keep blood pressure high in the lungs.
(C) Less carbon dioxide is removed from the body cells.
(D) Oxygen is supplied to body cells by blood at high pressure.
▶️ Answer/Explanation

In a double circulatory system, blood passes through the heart twice for every one complete circuit of the body. This separation allows the heart to pump blood to the lungs at a lower pressure to protect delicate tissues, while pumping blood to the rest of the body at a much higher pressure.

By re-pressurizing the blood after it returns from the lungs, the system ensures that oxygenated blood reaches systemic tissues rapidly and efficiently. This supports a higher metabolic rate, which is essential for maintaining body temperature and high levels of activity. Options A and C describe disadvantages or inefficiencies, while B is incorrect because lung capillaries require lower pressure to prevent fluid buildup.

✅ Answer: (D)

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