11. in single-gene traits, natural selection can lead to which of the following?
a. founder effect
b. disruptive selection
c. allele frequency change
d. directional selection

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.

i think the answer is b.