Mechanical digestion begins in the mouth as the food is chewed. Chemical digestion involves breaking down the food into simpler nutrients that can be used by the cells. Chemical digestion begins in the mouth when food mixes with saliva. Saliva contains an enzyme (amylase) that begins the breakdown of carbohydrates.
True but in more depth they both have the some same qualities in function but provide for each other when one makes oxygen, H2O, and energy and cellular respiration makes CO2 and glucose
