3.4 The Circulatory System in Animals

Why do large animals require a circulatory system instead of relying solely on diffusion?

• Diffusion is too slow in large organisms.

• Diffusion provides more energy.

• Circulatory systems are only for small organisms.

• Diffusion increases waste removal speed.

What is one of the main functions of the circulatory system in animals?

• To deliver oxygen and nutrients to cells

• To produce energy directly

• To slow down metabolism

• To store waste products

Which of the following is an example of a waste product that must be removed efficiently by the circulatory system?

• CO₂

• Glucose

• Amino acids

• Oxygen

Which of the following best describes an open circulatory system?

• Blood is always contained within vessels and circulates rapidly.

• Blood is not always in vessels and moves more slowly.

• Blood is pumped directly to the lungs for oxygenation.

• Blood is only found in the heart.

What is a key advantage of a closed circulatory system compared to an open circulatory system?

• It is slower and less efficient.

• It allows blood to leave the vessels and bathe organs directly.

• It is faster and more controlled.

• It is only found in insects.

What is a key characteristic of double circulation in the circulatory system?

• Blood passes through the heart only once

• Blood passes through the heart twice

• Blood does not pass through the heart

• Blood passes through the lungs only

What is the function of the pulmonary artery?

• Carries blood from the body to the heart

• Carries blood from the heart to the lungs

• Carries blood from the lungs to the heart

• Carries blood from the heart to the body

Which vessel returns oxygenated blood from the lungs to the heart in double circulation?

• Vena cava

• Aorta

• Pulmonary vein

• Pulmonary artery

Why does double circulation improve the efficiency of the circulatory system?

• It allows blood to bypass the lungs

• It ensures oxygenated and deoxygenated blood are separated, allowing for better oxygen delivery to tissues

• It reduces the number of capillaries needed

• It increases the heart rate

What is the name of the fluid in the open circulatory system of insects?

• Hemolymph

• Plasma

• Lymph

• Blood