During periods of vigorous physical activity, a person's breathing and heart rates increase. this enables the cells of the body to perform more efficiently because it the cells to

Remove the metabolic waste quickly

Explanation:

The increased breathing rate ensures intake of oxygen into the body while the increased heart rate leads to increased oxygen supply to the muscles. The oxygen serves to remove the metabolic waste (for example: carbon dioxide) produced during muscle contraction and thereby, enables the cells of the body to perform more efficiently.

the major parts of the digestive system:

salivary glands.

pharynx.

esophagus.

stomach.

small intestine.

large intestine.

rectum.

accessory digestive organs: liver, gallbladder, pancreas.