Question

multiple choice question
rate and depth of breathing will increase if carbon dioxide levels are
________ in the blood.
decreased
increased

Explanation:

When carbon dioxide levels increase in the blood, it leads to a decrease in blood pH (more acidic). The body's respiratory control centers (in the medulla oblongata and pons) detect this change. To restore the normal pH and gas balance, the body increases the rate and depth of breathing. This helps to expel more carbon dioxide (as \(CO_2 + H_2O
ightleftharpoons H_2CO_3
ightleftharpoons H^+ + HCO_3^-\), so removing \(CO_2\) shifts the equilibrium to reduce \(H^+\) concentration and raise pH). If carbon dioxide levels were decreased, there would be no such stimulus to increase breathing rate and depth.

Answer:

increased