Low genetic diversity? helps a population evolve
can result in extinction
is not a problem with modern-day organisims
is the main cause of mass extinctions

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.

some inherited genetic mutations can be good for the offspring, so the answer is different genetic mutations cause many forms of cancer.