Two populations that are separated by a mountain range can no longer interbreed to produce fertile offspring. this is an example of
a) allopatric speciation
b) niche speciation
c sympatric speciation
d subspecies speciation

a) allopatric speciation  

Explanation:

Allopatric speciation occurs when two populations of a species are separated by a geographical barrier. This geographical barrier, which can be a mountain, desert or forest, for example, causes a spatial separation (allopatry). In this case, we say that a geographic isolation occurred.

When these populations separate, they may undergo different pressures as they are in different areas. These pressures, over time, cause a genetic divergence and, consequently, a possible reproductive isolation. Many consider this type of speciation as the main model of speciation.

the answer is c. it will give up it's valence electron to the other atom.