Study the sectional view of human testis showing seminiferous tubules given below. Answer the questions that follow:
Identify a, b and c.

Why does meiosis and mitosis occur in germ cells?

First half of the menstrual cycle is called proliferative phase as well as follicular phase. Explain.

What are the events taking place in the ovary and uterus during follicular phase of the menstrual cycle?

Study the sectional view of human testis showing seminiferous tubules given below. Answer the questions that follow.
Write the functions of a and d.

What is the role of foetus in inducing parturition?

What is the number of chromosomes in the following cells of a human female?
Ootid.

Mention the number of cells in the following stages:

S. No	Embryonic stages	No. of cells
(i)	Zygote	______________
(ii)	Morula	______________
(iii)	Blastocyst	______________

How many spermatozoa are formed from one secondary spermatocyte?

List the four different human male accessory ducts.