Nitrogen is made available in a useful form for animals in the a. fertilizers they absorb. b. plants they eat. c. air they breathe. d. rainwater they drink.

The seed coat's most important function is to provide a) a nonstressful environment for the megasporangium. b) the means for dispersal. c) dormancy. d) a nutrient supply for the embryo. e) desiccation resistance.

Match the examples to the correct level of organization. 1. system level roses, snakes, puppies 2. organism level roots, stamens, leaves 3. tissue level bone, cartilage, blood 4. organ level heart, veins, arteries

Which phase of the cell cycle ensures that identical copies of the dna are made for daughter cells?