Allows ingestion and breaks down food so that nutrients can be absorbed???

Salivation allows the ingestion of food while digestive juices aids breakdown of food and absorption of nutrients.

Explanation:

When food is taken into the mouth, the presence of food triggers a nervous reflex that causes the salivary gland to produce saliva in the mouth. Once the food particles have been ingested the digestive system breaks down the food into smaller components with the aid of the digestive juices.

answer; i believe that the correct answer is (a); a large rock being weathered by wind and rain;

a:

by the combination of an unlimited number of elements