$(a)$ Explain,giving examples,how artificial selection has helped in the formation of newer varieties of cauliflower.
$(b)$ List the steps involved in the formation of new species.
$(c)$ How do different races of human beings belong to the same species?

(N/A) Artificial selection is the process by which humans breed plants or animals for particular traits. Over thousands of years,humans have selected different traits from the wild cabbage plant ($Brassica$ $oleracea$) to create various vegetables. For example,by selecting for sterile flowers,we developed cauliflower; by selecting for arrested flower development,we developed broccoli; and by selecting for swollen parts,we developed kohlrabi.
$(b)$ The formation of new species,known as speciation,involves the following steps:
$1$. Genetic variation within a population.
$2$. Geographical isolation (separation of populations by physical barriers).
$3$. Genetic drift and natural selection acting on isolated populations.
$4$. Reproductive isolation,preventing interbreeding between populations.
$(c)$ Different races of human beings belong to the same species ($Homo$ $sapiens$) because they share a common ancestor,have similar genetic makeup,and are capable of interbreeding to produce fertile offspring.