Using a molecular clock, clock, scientists are able to estimate the amount of time that two species have been evolving independently?

Yes

Explanation: The molecular clock is figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory with two or more life forms.

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.