Question

In many vertebrates, including humans, blood flows in two circuits; in an arrangement called double circulation. Which of the following is not an advantage of double circulation over the single circulation organization found in fish?

• A. There is greater surface area over which gas exchange between the blood and environment occurs, resulting in higher oxygen levels.
• B. Oxygenated blood can be mixed with deoxygenated blood before passing through the tissues of the body.
• C. The blood flows to the body tissues under higher pressure and faster, allowing for more efficient delivery of oxygen.
• D. Blood flow to different parts of the body can be regulated more precisely to meet localized oxygen needs.

Answer 1

The correct option is B

Oxygenated blood can be mixed with deoxygenated blood before passing through the tissues of the body.

Oxygenated blood can be mixed with deoxygenated blood before passing through the tissues of the body. Having a pulmonary circulation and pump that are separate from the systemic circulation and pump allows the systemic pump to re-pressurize the blood flow as it leaves the heart for the body's tissues. This increases the rate at which oxygen can be delivered to the tissues.