The theory of continental drift suggests that at one time,
a. the continents were all joined into one land mass
b. there was no land on the earth
c. there was no water on the earth
d. all continents were made of ice

the answer to your question is b

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.