Which statement is not true about thyroxine?

The shape of guard cells changes due to change in the :

Which is the main thinking part of the brain? State how it functions.

The hormone which increases fertility in males is called:

Why is the flow of signals in a synapse from the axonal end of one neuron to the dendritic end of another neuron,but not in the reverse direction?

Answer the following:
$(a)$ Which hormone is responsible for the changes noticed in females at puberty?
$(b)$ Dwarfism results due to deficiency of which hormone?
$(c)$ Blood sugar level rises due to deficiency of which hormone?
$(d)$ Iodine is necessary for the synthesis of which hormone?