The ovum is released from the ovary in the ............. stage.

When a male ejaculates sperms during coitus,for normal fertility,at least ....... percent of sperms must have normal shape and size,and at least ........... percent of them must show vigorous motility.

State the site of the process of oogenesis.

Draw a labeled diagram of a human sperm cell.

When is the polar body extruded from the oocyte?

In mammals,growing oocytes are surrounded by special nutritive cells called: