Identify the bonds that form between each of the following pairs of atoms as nonpolar-covalent, polar-covalent, or ionic: 1. C and F
2. Cl and Br
3. I and I
4. Ca and Cl

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.