Three different alleles (c1, c2, and c3) at the c locus exist in a hypothetical population of juniper trees. if the frequency of c1 is 0.3, the frequency of c2
a) cannot be less than 0.3.
b) cannot be greater than 0.3.
c) is 0.7.
d) cannot be greater than 0.7.

d

Explanation:

When considering the frequency of the potential alleles of a gene in a population, the total must add up to 1. Think of it like percentages. an allele frequency of 0.3 means 30% of the population carry it (out of a possible 100%).

We know that the frequency of c1 is 0.3. Lets take each option and see if it can be true

a) cannot be less than 0.3.  - false. It could be less than 0.3. For example, it could be 0.1, meaning the frequency of allele c3 would be 0.6 (because 0.3 + 0.1 + 0.6 = 1)

b) cannot be greater than 0.3. - false. It could be greater than 0.3. For example, it could be 0.5, meaning the frequency of allele c3 would have to be 0.2 (because 0.3 + 0.5 + 0.2 = 1)

c) is 0.7.  - false. It can't be 0.7, because that would mean that the frequency of c3 is 0. (0.7 + 0.3 = 1)

d) cannot be greater than 0.7. - true. It cannot be greater than 0.7, because  that would mean that the frequency of c3 is 0. (0.7 + 0.3 = 1)