In an experiment, the group that is expossed to the variable to be tested is called what

Rank the three variables in terms of how strongly they affect the "species" composition of the bacterial communities. place the variable with the weakest effect on the left and the variable with the strongest effect on the right.

Which conditions are necessary for natural selection to occur? select all of the answers that apply. a. inheritable adaptations vary among individuals. b. the population size is increasing. c. more individuals are born than can survive. d. fitness varies among individuals. e. the environment changes suddenly and drastically.

Q: a: in sexually reproducing animals, once fertilization of the egg takes place, the exists as a single cell until cell division begins