Which phrase listed below best describes the function of the digestive system?
a. to filter out waste from the blood
b. to remove waste from the body
c. to break down food into nutrients
d. to protect the body against germs
b?

C is the correct answer. The main function of the digestive system is to break down food into nutrients.

Food is needed to fuel the body for energy, and also for growth and repair. The digestive system converts the food we eat into their simplest forms , like glucose, amino acids and fatty acids. The broken down food is then absorbed into the bloodstream from the small intestine and the nutrients are carried to each cell of the body.

The large intestine  serves as a storage organ for the excretory products. However though this is true, the main function of the digestive system is to break down food into nutrients. The excretory duty is more of a necessity rather than a primary function.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.