Why is it useful to have lots of capillaries inside each of the villi? (villi are things on the inner surface of the small intestine)

In addition to seeds, which of the following characteristics are unique to the seed-producing plants? a) sporopollenin b) lignin present in cell walls c) pollen d) use of air currents as a dispersal agent e) megaphylls

Give an example of a trait that is controlled by more than one gene.

How water is moving through the ecosystem ?