Answer:
A geneticist studied a large grass population growing in an area of erratic rainfall and found that plants with alleles for curled leaves reproduced better in dry years and plants with alleles for flat leaves reproduced better in wet years. This situation would preserve the variability in the grass population.
Step-by-step explanation:
As described above, the curled leaves can maintain themselves and reproduce during the dry season whereas the flat leaves plants can maintain and reproduce during wet years. As a result, both the curled leaves and flat leaves plants will be able to establish in this land. There will not be chances of extinction of any one of them. The number of both the curled leave plants and flat leave plants will be round about same.