An astronaut travels from earth to the moon. the moon is much smaller than earth. which statement describes what happens to the astronaut as he approaches the moon? a. his weight decreases. b. his weight increases. c. his mass decreases. d. his mass increases.

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.