According to scientific thought, when does one species of organisms become two species?

a.
when populations become separated from one another

b.
when one population becomes extinct

c.
when one population cannot interbreed with the other population

d.
when populations compete for the same resources

8) animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. d) a dog is getting hot in the sunlight, so he moves to a shaded area.