Digestion is the process by which the body breaks down food into nutrients it can use for energy. There are two types of digestion: mechanical and chemical. Mechanical digestion is the physical breaking down of food. It is like slicing an onion with a knife. Chemical digestion is the breaking down of food using acids or enzymes. It is like soaking sliced onions in vinegar to soften them.
Which of these is an example of mechanical digestion?
A
food moving down the esophagus
B
teeth biting and grinding food into a paste
C
saliva softens food chemically in the mouth
D
nutrients being absorbed into the bloodstream
B
teeth biting and grinding food into a paste