The best classification system is that which most closely a. unites organisms that possess similar morphologies. b. conforms to traditional, linnaean taxonomic practices. c. reflects evolutionary history. d. corroborates the classification scheme in use at the time of charles darwin. e. reflects the basic separation of prokaryotes from eukaryotes.

One of the largest seafood exporters to the united states is a. china b. brazil c. mexico d. saudi arabia

What are the doorways into and out of cells, attached to the membrane, and built in the rough er.

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.