Allele frequencies can change across the geographic range of a species according to climate, geological features, or direction in the range. for instance, a certain allele frequency might go up along with the elevation or down as you go south in the species' range. this systematic change in frequency is referred to as
a. genetic drift.
b. q2.
c. directional selection.
d. a cline.
e. heterosis.

Cline

Explanation:

Cline refers to a noticeable and gradual change of some phenotypic traits over a geographical region. The phenotypic traits such as body size, coloration, etc. exhibit continuous variation or gradient over a geographical region.

Clines result from geographical variations within a species. Clines are usually related to the gradient of abiotic factors such as temperature, pressure, light, altitude. Gene flow between the populations present along the gradient of abiotic factors results in continuous variations in allele frequencies.

Microevolution

Step-by-step explanation:

It is a systematic change in allele(gene) frequency in a population of living organisms over a certain period of time.This change maybe caused by :

1.Mutation-A change in genetic composition of an organism due to environmental factors such as the excessive exposure of an organism to radiation.

2.Natural selection-Which occurs when some organisms have to survive a changing environment as a result of the possesion of some beneficial traits.

3.Gene flow-which involves the transfer of genes from one population to another.

4.Genetic drift-which is a difference or variation in the genetic make-up among organisms of the same species.