House sparrows in the northern part of north america are larger than those found in the southern regions. which mechanism of microevolution is more likely to be responsible for this?
a.) founders effect
b.) natural selection
c.) genetic drift

The correct answer will be Option-B

Explanation:

Micro-evolution represents the change in the frequency of the genes in populations in a small period of time and thus can be observed easily.

The case of the House sparrows which were introduced in the colder climates of North America in 1852 grew larger in size as compared to the sparrows of South America.  

This change in the size happened as a result of the natural selection in which the colder climate selected the sparrows with large body size and thus large size of the body was passed on the generations and became permanent.

Thus, Option-B is the correct answer.

amber has allowed scientists to study dna that has been preserved over millions of years.