Other than water, what else expands when frozen?

Why do you think the puppy litter was all dark-haired?

2. sketch the inside of the bean nodule, and describe or label what you observed with the hand lens.

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.