Answer: Saliva
Explanation: Saliva is present in the mouth, and is secreted from the salivary glands. It contains enzymes which start the digestion of food in mouth itself. It contains three enzymes-
1. Amylase- breaks down starch into maltose & glucose
2. Maltase- breaks down maltose into glucose
3. Lipase- breaks down fats present in the milk.
Ovary is a part of reproductive system. And, capillary & diaphragm is part of respiratory system.