Answer: The correct answer is option a.
Explanation:
Prezygotic isolation is a mechanism by which mating and fertilization is prevented. Thus, it prevents the formation of a zygote.
It can be achieved by various reasons such as temporal differences (difference in mating seasons), habitat isolation, behavioural differences (different mating rituals such as different dance patterns, voice calls, et cetera), mechanical isolation, et cetera.
Thus, different breeding calls prevent the species to interbreed with each which ultimately prevent the formation of zygote formation.
Hence, it is a type of prezygotic isolation.
After the macrophage fails the Helper T Cell stimulates the B cells if pathogen is extracellular and Cytotoxic T Cells if the pathogen is intracellular. Once the pathogen is killed the B Cells create Memory B Cells and the Killer T Cells create memory T Cells.
Answer:
The light colored pepper moths were able to camouflage in the Birchwood trees unlike the darker ones. But when the industrial revolution came the amount of smoke from the factories made the Birchwood trees become darker in color do now the darker pepper moths were the ones who could camouflage while the white ones were easily eaten and killed. Since the darker colored moths were able to survive they had offspring who were also darker colored. Over time since mainly darker moths were produced it was common for pepper moths to be darker.
The answer to ur question is A
