Question

Yawning is a reflexive action that is often associated with sleepiness. when a person yawns, the mouth opens, and a longer than normal breath of air is inhaled, followed by a longer than normal exhalation. hypothesizing that yawning has a regulatory mechanism similar to breathing, scientists conducted an experiment on college students to test the effect of ambient carbon dioxide levels on yawning. the scientists investigated carbon dioxide levels in their experiment because high carbon dioxide levels in the ________ signal control centers in the brain to increase rate and depth of inhalations and exhalations.

Answer 1

The correct answer in the blank is arterial blood.

Step-by-step explanation:

The elevated levels of CO2 in the arterial blood signals the brain to increase the rate and depth of inhalations and exhalations.

Blood in the veins normally has the high concentration of CO2.

Arterial blood contains very low level of CO2 and High level of CO2 in this blood signals brain to increase breathing rate.

Answer 2

The level of carbon dioxide in the arterial blood which is the answer signals the control centers in the brain to increase the rate as well as the depth of breathing specifically the inhalation and exhalation. Arterial blood is the oxygenated blood in one's circulatory system.