Answer:
homologous, high levels of, natural selection
Feeling pain, hunger, thirst, sleepiness, and being aware of our thoughts and emotions are all examples of Internal stimuli.
Good morning!! The purpose of both a dichotomous key and a field guide's purpose is to identify organisms. The only difference between the two is the a dichotomous key just uses descriptions to identify the animal with no pictures, but a field guide uses pictures to identify the organism. Another thing that separates the two is that the dichotomous key gives questions/descriptions that describe the organism, whereas the field guide uses a brief description of the animal. Hope I helped!!