Write true or false for the statement: Deficiency of calcium in our diet causes goitre.

Iodine is necessary for the synthesis of which hormone?

$(a)$ An old man is advised by his doctor to take less sugar in his diet. Name the disease from which the man is suffering. Mention the hormone due to imbalance of which he is suffering from this disease. Which endocrine gland secretes this hormone?
$(b)$ Name the endocrine gland which secretes growth hormone. What will be its effect on a person of:
$(i)$ Deficiency of growth hormones?
$(ii)$ Excess secretion of growth hormones?

Choose the incorrect statement about insulin:

Which part of the neuron receives messages from sensory organs?

Which of the following statements are true?
$(i)$ Sudden action in response to something in the environment is called reflex action.
$(ii)$ Sensory neurons carry signals from spinal cord to muscles.
$(iii)$ Motor neurons carry signals from receptors to spinal cord.
$(iv)$ The path through which signals are transmitted from a receptor to a muscle or a gland is called reflex arc.