Polar hormones cannot cross the plasma membrane thus use a system to activate specific proteins within the cytoplasm.

Which of the following is a good definition for the word adaptation? question 1 options: a trait that an organism survive and reproduce in its environment. a change in an organism's environment. the way in which animals obtain food. a temperature change that can cause the extinction of plants and animals.

In "the pig," what is the main effect that the piglet initially has on kibuka?

Which of the following organisms are capable of self-fertilization? a.plants b.tigers c.humans