Light bends as it passes through substances of different densities, a process known as:

Which of the following describes a boom period? a. as one population increases, another population decreases. b. as one population increases, the other population also increases. c. as one population decreases, another population increases. d. as one population decreases, another population also decreases

Which kind of worm has a closed circulatory system? a planarian b fluke c pinworm d an earthworm

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic