Sunflowers orient themselves towards the direction of sunlight. What type of tropism is this?

In what form is the response to a stimulus generally observed in body parts?

$(a)$ Name the diseases by which a person is likely to suffer due to the deficiency of:
$(i)$ Iodine
$(ii)$ Insulin
$(b)$ How are the timing and amount of hormone secretion regulated in the human system? Explain with an example.

Deficiency of which hormone in the body causes diabetes?

$(a)$ Draw the structure of a neuron and label the following on it:
Nucleus,Dendrite,Cell body,and Axon.
$(b)$ Name the part of the neuron:
$(i)$ Where information is acquired.
$(ii)$ Through which information travels as an electrical impulse.

All information from our environment is detected by specialised tips of some nerve cells. Write the name given to such tips and also mention where they are located.