Multicellular organisms undergo cell specialization in order to create organization within the body. which of the following would not be an example of cell specialization?
a. pancreatic cell that produces protein-digesting enzymes.
b. muscle cells that control movement of materials in the body
c. a prokaryotic cell that carries out photosynthesis.
d. a red blood cell that carries oxygen.

Lactase is essential for digesting lactose in milk. this enzyme is specific for this sugar. why? molecules and active sites vary in size; only properly sized molecules can fit. there is a precise compatibility between the active site and the lactose molecule. specificity refers to the action of the enzyme, such as hydrolysis, and relatively few molecules can be hydrolyzed. reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules.