Question

An insect population lives along the edge of a north-south mountain range. The populations from the east and west slope eventually join in a low northern pass and interbreed, producing fertile offspring; but they do not circle around the southern edge because of a desert barrier. When glaciers move southward, the populations are pushed south of the northern pass and are isolated. While isolated, the two populations develop enough differences over time that when the glaciers retreat north and the insects again share the same pass, they no longer mate at the same time, nor can they produce fertile offspring. These insects _____.

Answer 1

Answer: They were originally one species but are now two species

Explanation:

The two insects first belong to the same species but due to the geographical isolation both of the species are separated.

The species earlier used to live in the same geographical area but due to barrier they got separated and now their time of mating is also different.

They have developed differences over a period of time but at some point of time they belonged to the same species.