Question

if a small number of tree frogs move from one population to a geographically isolated population of tree frogs and introduce new alleles into the native populations gene pool, the change is referred to as
a. the bottleneck effect.

b. directional selection.

c. genetic drift.

d. gene flow.

Explanation:

Gene flow is defined as the transfer of genetic material (like new alleles) between populations, which matches the scenario of new tree frogs introducing new alleles into a native population's gene pool. The bottleneck effect is a reduction in population size causing genetic loss; directional selection is a type of natural selection favoring a trait extreme; genetic drift is random change in allele frequencies, none of which fit the described scenario.

Answer:

D. gene flow.