Final answer:
The missing words in the given pairs are lipase, trachea, living tissue, and lipids/fatty acids.
Step-by-step explanation:
The missing word in the first pair is lipase, as salivary amylase breaks down starch and pancreatic lipase breaks down lipids. In the second pair, the missing word is trachea, as the nasal cavity connects with the uvula and the trachea connects with the esophagus. For the third pair, the missing word is living tissue, as enamel is part of teeth and dentine is a component of living tissue. Finally, the missing words in the fourth pair are lipids or fatty acids, as glucose is transported by blood capillaries and fatty acids and glycerol are transported by lipids.