IGCSE Biology Topic 9: Transport in Animals MCQs – 30 Practice Questions with Answers (Cambridge 0610)
Free practice for Cambridge IGCSE Biology 0610 on transport in animals, covering the heart, double circulation, blood vessels and blood, with every question followed by a short worked explanation.
The Heart and Double Circulation
Q1. Which description best defines the mammalian circulatory system?
- (A) A set of nerves carrying impulses from the brain to the muscles
- (B) A set of tubes carrying air from the nose to the lungs
- (C) A system of blood vessels with a pump and valves
- (D) A set of glands releasing hormones directly into the gut
Show Answer
Answer: C – The heart pumps blood through vessels, and valves prevent backflow so blood keeps moving in one direction.
Q2. In the mammalian heart, which chambers receive blood returning to the heart?
- (A) The left and right atria
- (B) The left and right ventricles only
- (C) The septum and the coronary arteries
- (D) The aorta and the vena cava
Show Answer
Answer: A – Blood enters the atria first, then passes down into the ventricles, which pump it out of the heart.
Q3. Why is the muscle wall of the left ventricle much thicker than that of the right ventricle?
- (A) The left ventricle beats faster than the right ventricle
- (B) The left ventricle contains more valves than the right
- (C) The left ventricle stores blood for longer between beats
- (D) The left ventricle pumps blood around the whole body
Show Answer
Answer: D – Pumping blood all around the body needs far more pressure than pumping it the short distance to the lungs, so the left ventricle has thicker muscle.
Q4. What is the function of the septum in the mammalian heart?
- (A) To pump blood into the coronary arteries
- (B) To keep the two sides of blood apart
- (C) To open and close the semilunar valves
- (D) To carry impulses that set the heart rate
Show Answer
Answer: B – The septum is a muscular wall down the middle of the heart that keeps the two sides of blood apart, so they do not mix.
Q5. Which sequence correctly follows blood through a double circulation, starting at the heart?
- (A) Heart, body, heart, lungs, heart
- (B) Heart, lungs, body, heart
- (C) Heart, lungs, heart, body, heart
- (D) Lungs, heart, lungs, body
Show Answer
Answer: C – In a double circulation, blood passes through the heart twice per circuit: once on its way to the lungs and once on its way to the body.
Q6. What is the main advantage of a double circulation over the single circulation of a fish?
- (A) Blood is repressurised before going to the body
- (B) Blood passes through the gills twice, so it picks up twice as much oxygen
- (C) The heart needs only one chamber instead of four
- (D) Blood flows more slowly, so more time is available for exchange
Show Answer
Answer: A – Repressurising blood in the heart after it leaves the lungs keeps the flow to body tissues fast, which supports a high metabolic rate.
Q7. During one heartbeat, in which order do the chambers contract?
- (A) Ventricles first, then atria, then both together
- (B) Left side first, then right side
- (C) Atria and ventricles contract at exactly the same moment
- (D) Atria contract first, then the ventricles contract
Show Answer
Answer: D – Atrial contraction fills the ventricles, and ventricular contraction then forces blood out through the arteries while the valves prevent backflow.
Q8. Which valves prevent blood flowing back from the ventricles into the atria?
- (A) The semilunar valves, at the bases of the aorta and pulmonary artery
- (B) The atrioventricular valves, between each atrium and its ventricle
- (C) The valves in the veins of the legs
- (D) The valves in the pulmonary vein
Show Answer
Answer: B – Atrioventricular valves close when the ventricles contract, while semilunar valves stop backflow from the large arteries into the ventricles.
Q9. A doctor listens to a patient’s heart and counts the pulse at the wrist. What do these checks reveal?
- (A) Heart activity, including heart rate
- (B) The oxygen concentration of the blood in the veins
- (C) The number of red blood cells in a sample of blood
- (D) The blood pressure inside the capillaries
Show Answer
Answer: A – Pulse rate reflects how often the heart beats, and the sounds heard are the valves closing; an ECG trace gives further detail on heart activity.
Q10. Why does heart rate rise during physical activity?
- (A) The heart muscle becomes thinner and beats less forcefully
- (B) The lungs stop exchanging gases, so the heart compensates
- (C) Active muscles need more oxygen and glucose
- (D) Blood vessels in the skin close, forcing the heart to work harder
Show Answer
Answer: C – Faster circulation delivers oxygen and glucose to respiring muscles more quickly and carries carbon dioxide away.
Q11. In a fish, blood flows from the heart to the gills, then to the body, then back to the heart. What type of circulation is this?
- (A) A double circulation, because blood passes the heart twice
- (B) An open circulation, because blood leaves the vessels
- (C) A pulmonary circulation only
- (D) A single circulation
Show Answer
Answer: D – In a fish the heart pumps blood once per circuit, and pressure falls as blood passes through the gills before reaching the body.
Q12. Which blood vessel carries deoxygenated blood away from the heart to the lungs?
- (A) The pulmonary vein, carrying blood from the lungs to the heart
- (B) The pulmonary artery
- (C) The aorta
- (D) The renal vein
Show Answer
Answer: B – The pulmonary artery is the exception to the usual rule: it is an artery because it carries blood away from the heart, but its blood is deoxygenated.
Blood Vessels
Q13. Which structural feature distinguishes an artery from a vein?
- (A) Arteries have thick, elastic walls and a narrow lumen
- (B) Arteries have valves and a wide lumen, while veins have thick, elastic walls
- (C) Arteries have walls one cell thick, while veins have walls several cells thick
- (D) Arteries carry blood towards the heart, while veins carry blood away from it
Show Answer
Answer: A – Blood leaves the heart at high pressure, so arteries need strong, stretchy walls; veins carry low-pressure blood and use valves to stop backflow.
Q14. Why do veins have valves but arteries generally do not?
- (A) Valves in veins speed blood up to match arterial pressure
- (B) Valves in veins filter out pathogens from the blood
- (C) Blood pressure in veins is low, so valves prevent backflow
- (D) Valves in veins produce red blood cells
Show Answer
Answer: C – With little pressure pushing it along, venous blood could flow backwards, so valves hold it in one direction towards the heart.
Q15. Which feature of capillaries best suits them for exchange of substances with tissues?
- (A) Thick, muscular walls that pump blood through tissues
- (B) Valves that stop blood flowing backwards
- (C) Elastic walls that stretch with each heartbeat
- (D) Walls only one cell thick
Show Answer
Answer: D – A one-cell-thick wall lets oxygen, glucose and other substances diffuse quickly between blood and tissue cells.
Q16. Blood in the aorta is oxygenated, while blood in the vena cava is deoxygenated. Which statement explains this difference?
- (A) The aorta carries blood to the lungs, where it loses oxygen
- (B) The aorta carries oxygenated blood to the body
- (C) The vena cava carries blood from the heart to the kidneys
- (D) The aorta carries blood only to the heart muscle itself
Show Answer
Answer: B – The aorta is the main artery leaving the left ventricle for the body, and the vena cava is the large vein bringing blood back to the right atrium.
Q17. Which vessel carries blood from the kidneys back towards the heart?
- (A) The renal vein
- (B) The renal artery
- (C) The hepatic portal vein
- (D) The pulmonary vein
Show Answer
Answer: A – The renal artery brings blood to each kidney, and the renal vein carries blood away from the kidney towards the heart.
Q18. Which vessel carries digested food in the blood from the gut towards the liver?
- (A) The hepatic artery, carrying oxygenated blood to the liver
- (B) The hepatic vein
- (C) The hepatic portal vein
- (D) The renal artery
Show Answer
Answer: C – The hepatic portal vein collects blood from the digestive organs and delivers it to the liver, where nutrients can be processed.
Q19. A capillary bed in a muscle is compared with an artery supplying it. Which comparison is correct?
- (A) The capillary has a thicker wall and a narrower lumen than the artery
- (B) The capillary has valves, while the artery does not
- (C) The capillary has a much higher blood pressure than the artery
- (D) The capillary has a far thinner wall and a much smaller diameter than the artery
Show Answer
Answer: D – Capillaries are tiny vessels with one-cell-thick walls, suited to exchange, while arteries are larger vessels with thick walls.
Q20. Why does blood pressure fall as blood passes from arteries into capillaries?
- (A) Valves in the capillaries block the flow
- (B) The total cross-sectional area increases and friction rises, so pressure drops, protecting the delicate capillary walls
- (C) The heart stops beating while blood is in the capillaries
- (D) Blood cells are removed in the capillaries
Show Answer
Answer: B – Branching into many capillaries spreads the flow, and the resulting pressure drop means thin capillary walls are not damaged.
Blood and Coronary Heart Disease
Q21. Which component of blood transports oxygen, and how does it do so?
- (A) Red blood cells, using haemoglobin to bind oxygen
- (B) White blood cells, using antibodies to bind oxygen
- (C) Platelets, using fibrin to bind oxygen
- (D) Plasma, using dissolved starch to bind oxygen
Show Answer
Answer: A – Red blood cells are packed with haemoglobin, which picks up oxygen in the lungs and releases it in respiring tissues.
Q22. Which two roles are carried out by white blood cells?
- (A) Carrying oxygen and clotting the blood
- (B) Carrying hormones and dissolving fibrin
- (C) Engulfing pathogens by phagocytosis and producing antibodies
- (D) Transporting urea and storing glucose
Show Answer
Answer: C – Phagocytes engulf pathogens, while lymphocytes produce antibodies that target specific pathogens.
Q23. What happens during blood clotting at a wound?
- (A) Red blood cells break down to release haemoglobin
- (B) White blood cells produce antibodies against the damaged tissue
- (C) Plasma proteins dissolve and the wound stays open
- (D) Fibrinogen is converted to fibrin, forming a mesh that traps blood cells and seals the wound
Show Answer
Answer: D – The fibrin mesh forms a clot that prevents blood loss and blocks the entry of pathogens.
Q24. Which substances are transported in the plasma?
- (A) Only red blood cells and platelets
- (B) Blood cells, ions, nutrients, urea, hormones and carbon dioxide
- (C) Only oxygen and antibodies
- (D) Only water and fibrinogen
Show Answer
Answer: B – Plasma is the liquid part of blood and carries cells plus dissolved substances, including nutrients, hormones, urea and carbon dioxide.
Q25. A person has a low platelet count. Which problem is most likely?
- (A) Their blood carries less oxygen to the tissues
- (B) Their blood clots more slowly, so wounds bleed for longer
- (C) Their blood cannot carry antibodies
- (D) Their blood pressure rises sharply
Show Answer
Answer: B – Platelets are involved in clotting, so fewer platelets mean clots form more slowly and bleeding lasts longer.
Q26. What is coronary heart disease, in terms of the heart’s own blood supply?
- (A) A blockage of the pulmonary artery, stopping blood reaching the lungs
- (B) A weakness of the septum, allowing oxygenated and deoxygenated blood to mix
- (C) A blockage of the coronary arteries, reducing the supply of oxygen and glucose to the heart muscle itself
- (D) A failure of the atrioventricular valves, causing blood to flow backwards
Show Answer
Answer: C – Coronary arteries supply the heart muscle, so a blockage starves that muscle of oxygen and glucose and can damage it.
Q27. Which combination lists only recognised risk factors for coronary heart disease?
- (A) A diet high in saturated fat, lack of exercise, smoking, stress, genetic predisposition, age and sex
- (B) Drinking water, eating fibre, walking daily and sleeping well
- (C) A diet high in fruit, regular exercise and low stress
- (D) Being young, never smoking and eating a balanced diet
Show Answer
Answer: A – The syllabus lists diet, lack of exercise, stress, smoking, genetic predisposition, age and sex as possible risk factors for coronary heart disease.
Q28. How can diet and exercise help reduce the risk of coronary heart disease?
- (A) They thicken the walls of the coronary arteries
- (B) A balanced diet low in saturated fat and regular exercise help keep the coronary arteries clear and the heart healthy
- (C) They stop the heart beating during rest
- (D) They replace the need for valves in the heart
Show Answer
Answer: B – Healthy diet and exercise reduce fatty deposits that can narrow coronary arteries and improve overall heart health.
Q29. Which statement correctly distinguishes lymphocytes from phagocytes?
- (A) Lymphocytes produce antibodies, while phagocytes engulf pathogens by phagocytosis
- (B) Lymphocytes carry oxygen, while phagocytes carry carbon dioxide
- (C) Lymphocytes form clots, while phagocytes produce plasma
- (D) Lymphocytes are found only in the heart, while phagocytes are found only in the lungs
Show Answer
Answer: A – Lymphocytes make specific antibodies, whereas phagocytes ingest and destroy pathogens directly.
Q30. A blood sample is spun to separate its components. Which layer would contain the plasma?
- (A) The thin white layer of white blood cells and platelets
- (B) The dark red layer of red blood cells at the bottom
- (C) The clotted fibrin mesh at the very bottom
- (D) The pale yellow liquid layer on top
Show Answer
Answer: D – Plasma is the pale yellow liquid that makes up the largest part of blood volume and sits above the cells when blood is separated.
Revisit any questions you missed, especially the vessels and the parts of the blood, then test yourself again until the double circulation feels secure.