Which is the male sex hormone?

Which of the following statements are true about the brain?
$(i)$ The main thinking part of the brain is the hindbrain.
$(ii)$ Centres of hearing,smell,memory,sight,etc.,are located in the forebrain.
$(iii)$ Involuntary actions like salivation,vomiting,and blood pressure are controlled by the medulla in the hindbrain.
$(iv)$ Cerebellum does not control posture and balance of the body.

How does the feedback mechanism regulate hormone secretion?

The shoot of a plant shows:

In which plant do flowers show photonastic movement?

Illustrate with the help of a diagram,the effect of auxins in different parts of a plant.