a. chemical digestion:
it the type of digestion which occurs due to enzymes start right from the mouth with help of amylase enzyme. some of it occurs in stomach, but the major part complete in small intestine.
b.secretion:
it is the phenomenon of release of enzyme, hormones and some salt in case of digestion.
c. mechanical digestion:
it is that type of digestion which occurs due to teeth, in which large food is broken down into small pieces to form bolus.
d. absorption:
it is the process in which food molecules are absorbed in villi in intestine.
Answer:
the correct option is a (chemical digestion).