When blood pH becomes overly acidic, respiration and kidney function change to bring the acidity back to its normal pH level of 7.4. What does this process best exemplify

homeostasis

Explanation:

Homeostasis has to do with processes that maintain the internal balance within an organism. It can succinctly be defined as the process of regulating an organism's internal environment. The process of homeostasis is very important in the maintenance of important indicators of balance in the body such as body temperature, body pH, etc.

Hence, when blood pH becomes overly acidic, respiration and kidney function change to bring the acidity back to its normal pH level of 7.4. This is a homeostatic response.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.

answerall of the above;