Semen consists of sperms only. Is this statement true? If no, name the other components along with their function.

The following illustration is the sequence of oogenesis in human female:

a) Mention the chromosome no. in a primary oocyte and a secondary oocyte respectively.
b) When is meiosis II completed in the oogenesis of human female?
c) At what stage is meiosis I suspended in a primary oocyte?

Study the figure given below and answer the question that follow:

a) Identify 'a' in the figure and mention its function.
b) Mention the stage of human embryo it follows.
c) Where are the stem cells located in this embryo?
d) Which part of this stage of human embryo gets attached to endometrium to establish pregnancy?

A mother gets infected with a virus which causes German measles during pregnancy. Is it possible that the foetus will also get infected? How ? What are its ill-effect on the foetus?

Why not all copulations lead to fertilisation and pregnancy?

What lead to menstruation in the absence of fertilisation?

What is the number of chromosomes in the following cells of a human male?
(i) Spermatogonial cells
(ii) Spermatids
(iii) Primary spermatocytes
(iv) Sertoli cells

Why is it considered that the presence or absence of hymen is not an indication of virginity?

(a) How many spermatozoa are formed from one secondary spermatocyte?
(b) Where does the first cleavage division of zygote take place?