Where are genes located?

$(a)$ 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?

Does geographical isolation of individuals of a species lead to formation of a new species? Provide a suitable explanation.

Which of the following is responsible for variation?

$(a)$ Which type of organs are shown in the figure below?
$(b)$ What is the origin and structure of these organs?

Which of the following statements is incorrect?