What roles does pituitary gonadotrophins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions. 

The zygote passes through several development stages till implantation.Describe each stage briefly with suitable diagrams.

With reference for events starting from menstrued cycle till the events of parturition give the name of the hormones involved at each stage and explain their role.

During the biology class, teacher was explaining the human reproductive system. Ankita was busy doing work of some other subject and so missed on the topic. When the teacher asked questions Ankita was unable to answer them. She, however, realised her mistake and requested the teacher to explain the topic once again. The teacher happily repeated.
(i) What is the primary sex organ in male?
(ii) What is tunica albuginea?
(iii) Name the three layers of tissue of uterus.
(iv) Identify the values shown by the teacher.

Vaibhav, 12th class student watched the movie 'Vickey donar'. He was very curious to know the structure and details of sperm. He wondered, why the donation of sperm is considered a taboo irrespective of the fact that it helps childless couples to have children. He discussed this whole thing with his elder brother, who is a biology professor in a university. His brother smiled and explained all his queries.
(i) Name the main parts of a sperm.
(ii) Which part of the human sperm is responsible for facilitating sperm motility? Explain.
(iii) What are the values shown by Vaibhav?