Which one of the following is the best definition of symbiosis?
a. predation of one species on another
b. dormant period of certain organisms during the winter
c. one kind of animal another
d. two species living in a long-term interrelationship

Cells tend to have a relatively small and uniform size. why aren’t cells larger?

What have we learned from fossil evidence about evolution? a) it is an abrupt change. b)the process is observable. c) it takes place during one lifetime only. d)the most complex traits are always selected.

Which of the following is the best definition of aerobic respiration? o a. the cellular process that releases energy by breaking down glucose o b. physical activity that involves the repeated motion of large muscle groups o c. physical activity that increases heart rate and breathing rate o d. the cellular process that converts solar energy to chemical energy