Question

1. which of the following best describes the internal feedback system that occurs between the respiratory system and the circulatory system? a. increased activity increases the need for oxygen within an organism. this stimulates an increase in the respiratory rate. an increased respiratory rate stimulates a decreased heart rate, which in turn causes additional oxygen to be supplied to the muscles. b. increased activity decreases the need for oxygen within an organism. this stimulates a decrease in the respiratory rate. a decreased respiratory rate stimulates a decreased heart rate, which in turn causes reduced amounts of oxygen to be supplied to the muscles. c. increased activity decreases the need for oxygen within an organism. this stimulates a decrease in the respiratory rate. a decreased respiratory rate stimulates an increased heart rate, which in turn causes reduced amounts of oxygen to be supplied to the muscles. d. increased activity increases the need for oxygen within an organism. this stimulates an increase in the respiratory rate. an increased respiratory rate stimulates an increased heart rate, which in turn causes additional oxygen to be supplied to the muscles.

Explanation:

When an organism's activity increases, the muscles need more oxygen. This stimulates an increase in heart rate to pump more blood (and thus oxygen) and an increase in respiratory rate to take in more oxygen.

Answer:

D. Increased activity increases the need for oxygen within an organism. This stimulates an increase in the respiratory rate. An increased respiratory rate stimulates an increased heart rate, which in turn causes additional oxygen to be supplied to the muscles.