How many lobes does the surface of the cerebral hemisphere possess?

Differentiate between estrogen and testosterone.

Plant roots grow towards water. What type of tropism is this?

Define neuron. Name the parts of the neuron where:
$(i)$ information is acquired?
$(ii)$ impulse must be converted into a chemical signal for onward transmission?

Select the mismatched pair:

Which statement is not true about thyroxine?