Two animals that can be found at the Grand Canyon include the Abert’s and Kaibab squirrels. The Abert’s squirrel is found at the south rim of the canyon and in a few surrounding states. The Kaibab squirrel, however, can only be found at the canyon’s north rim, mainly on the Kaibab Plateau. The Kaibab squirrel is not found anywhere else in the world. Scientists believe that the squirrels are actually closely related and have developed separately as a result of geographic isolation. It is possible that the squirrels were separated by plateau erosion that separated the forests and isolated the Kaibab population. Some scientists are studying if the squirrels are now two separate species or if the Kaibab squirrel is simply a subspecies of the Abert’s squirrel. Separate species are unable to reproduce with each other. Which evidence would be used to support the claim that the squirrels are two separate species?
The Abert’s squirrel is found at the south rim of the canyon, but the Kaibab squirrel is found at the north rim of the canyon.
Geologists prove that plateau erosion is the main cause of forest separation in the region.
Scientists observe that Abert’s squirrels are slightly larger and have bushier tails than Kaibab squirrels do.
When placed together in pairs for study, no pair of Abert’s squirrel and Kaibab squirrel result in offspring.

Evidence which would be used to support the claim that the squirrels are two separate species is When placed together in pairs for study, no pair of Abert’s squirrel and Kaibab squirrel result in offspring.

Explanation:

The Albert's squirrels are found at the south rim.

The Kaibab's squirrel are found in north rim.

They have become two species (speciation) due to geographic isolation and are called allopatric speciation.

The speciation occurring due to geographical isolation would not produce offsprings. This is due to the reproductive isolation in the squirrel population. The two species of squirrels are having different habitats and they reproduce at the different times of the year hence no mating would take place due to temporal isolation of the two species. There is also a chance of behavorial isolation as two species might have different mating preferences.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation:

answer; i believe that the correct answer is (lung);