Let me just summarize how digestion moves down the different organs. A is the mouth used for chewing and saliva moisten and starts to digest the food. It then travels down B to C (stomach), where it is further digested before moving to D (small intestine) . At D, digestion is completed and digested food is absorbed into blood and transported to other parts of the body. Undigested food is transported to E (large intestine) where excess water is absorbed. The resulting waste is released from F (rectum).

(A) (ii) the area where water is removed from undigested food would be the large intestine (E)

(B) saliva is from the mouth. Any function works but the most obvious one would probably be saliva helps to moisten the food to make it easier to swallow.

(C) the digested food is absorbed into the blood vessels at the small intestine. The food can then be transported to other parts of the body for energy.