Question 1

Which of the following best explains why diffusion alone is insufficient for gas exchange in large multicellular animals?

Accepted Answer

Diffusion is only effective over short distances due to the time required for molecules to move across larger areas.

Question 2

Which of the following organisms possesses a closed circulatory system?

Accepted Answer

Annelids (e.g., earthworms)

Question 3

What is the primary advantage of a double circulatory system over a single circulatory system in vertebrates?

Accepted Answer

It allows separation of oxygen-rich and oxygen-poor blood, supporting higher metabolic rates.

Question 4

In the context of gas transport, which equation correctly represents the reversible reaction that allows most carbon dioxide to be transported in the blood?

Accepted Answer

$$\mathrm{CO_2$ + H_2O \leftrightarrow H_2CO_3 \leftrightarrow H^+ + $$HCO_3$$^-}$$

Question 5

A patient has a mutation that reduces the affinity of hemoglobin for oxygen. Which of the following is a likely physiological consequence?

Accepted Answer

Reduced oxygen delivery to tissues, especially during exercise.

Question 6

Which statement correctly distinguishes arteries from veins in the vertebrate circulatory system?

Accepted Answer

Arteries carry blood away from the heart, while veins carry blood toward the heart.

Question 7

In a fish with single circulation, what is the correct sequence of blood flow starting from the heart?

Accepted Answer

Heart → gills → body → heart

Question 8

Which of the following best describes the role of hydrostatic pressure in a closed circulatory system?

Accepted Answer

It is the force generated by the heart that drives blood through vessels.

Question 9

Which of the following is NOT a component of blood in a closed circulatory system?

Accepted Answer

Hemolymph

Question 10

A researcher observes an animal with a heart that pumps blood into vessels, which then open into body cavities where organs are bathed directly in the fluid. Which type of circulatory system is this?

Accepted Answer

Open circulatory system

Question 11

Which of the following best explains why the left ventricle of the mammalian heart has a thicker muscular wall than the right ventricle?

Accepted Answer

It must generate higher pressure to distribute blood throughout the systemic circuit.

Question 12

Which of the following is the main form in which carbon dioxide is transported from tissues to the lungs?

Accepted Answer

As bicarbonate ions ($$\mathrm{$$HCO_3$$^-}) in $$plasma

Question 13

Which of the following best describes the function of capillaries in the closed circulatory system?

Accepted Answer

They are the sites where exchange of gases, nutrients, and wastes occurs between blood and interstitial fluid.

Question 14

A patient is experiencing low blood pressure after severe blood loss. Which of the following is a likely consequence for tissue oxygenation?

Accepted Answer

Reduced delivery of oxygen and nutrients to tissues due to insufficient hydrostatic pressure.

Question 15

Which of the following statements about hemoglobin is correct?

Accepted Answer

Each hemoglobin molecule can bind up to four oxygen molecules because it has four heme groups.

Question 16

Which of the following best describes the evolutionary significance of the development of a closed circulatory system in vertebrates?

Accepted Answer

It enabled efficient transport of oxygen and nutrients, supporting larger and more active body sizes.

Question 17

In the context of cardiovascular systems, what is the main limitation of an open circulatory system for large, active animals?

Accepted Answer

It cannot efficiently deliver oxygen to tissues at high metabolic rates.

Question 18

Which of the following best describes the sequence of events for carbon dioxide removal in the lungs?

Accepted Answer

Bicarbonate re-enters red blood cells, combines with H$$^+ to $$form carbonic acid, which decomposes to CO$$_2$$ and H$$_2O$$; CO$$_2$$ then diffuses into the alveoli.

Question 19

Which of the following is a correct statement about the relationship between pressure and flow in the double circulatory system of mammals?

Accepted Answer

The pulmonary circuit re-pressurizes blood before it enters the systemic circuit, ensuring efficient delivery to tissues.

chapter 34

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