Which statement about natural selection is true? a. environmental changes determine which animals survive. b. environmental changes drive differential reproduction. c. overproduction of offspring drives environmental changes. d. differential reproduction causes environmental changes.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.

unicellular organisms, like bacteria, are able to perform all life functions within one single cell. multicellular organisms need many different types of cells to carry out the same life processes. each of these special types of cells has a different structure that it perform a specific function.