Which of the following describes the main role of the electron transport chain in cellular respiration? a. it pumps hydrogen ions inside the cell b. it produces the energy carriers c. it produces molecules of atp d. it breaks down glucose molecules apex ?

A.it pumps hydrogen ions inside the cell

Explanation:

Principally, the main role of electron transport chain is to maintain the electrochemical gradient of hydrogen ions (H+) inside the mitochondrial matrix. This is the last step in aerobic cellular respiration and performs a series of redox reactions. Overall, it allows accumulation of H+ inside the mitchondrial matrix. This increased gradient or accumulation of hydrogen ions (H+) is essential because H+ would accept the electrons producing during the reactions. Without this, the flow of electron will be stopped because of high  gradient, and production of ATP will not happen as well.

Indeed ETC helps in production of ATP but that is not the main function of electron transport chain rather it is a function of mitochondria.

the major parts of the digestive system:

salivary glands.

pharynx.

esophagus.

stomach.

small intestine.

large intestine.

rectum.

accessory digestive organs: liver, gallbladder, pancreas.