Scientists discovered a fossilized cockroach trapped in amber, which was supposed to be about 50 million years old. dna fingerprinting and comparison with today's living cockroaches revealed that modern cockroaches have certain additional genes which allow them to survive in today's colder climate. which of these could be the correct explanation for this discovery?

The answer is change in gene frequency of ancient cockroaches led to the evolution of modern cockroaches.

Let's suppose that 50 million years ago there was a population of cockroaches with great diversity. There were cockroaches with genes which allow them to survive in today’s colder climate and as well cockroaches without these genes, both groups with different gene frequencies. But, after the climate started getting cold, only those cockroaches with genes which allow them to survive in older climate could survive and reproduce. Thus, their frequency increased.