Thyroxin was isolated by

Consider the following statements with respect to Calcitonin:
$I$. It is non-iodised.
$II$. It is secreted by parafollicular cells.
$III$. It regulates the calcium level in blood.
$IV$. It is also called as $TCT$ (Thyrocalcitonin).
$V$. It is a hyperglycemic agent.
Select the option containing correct statements from the above given statements.

The thyroid gland is homologous to which part of lower vertebrates?

Goitrogenic substances present in food,which interfere with the secretion of thyroxine,induce the development of:

Assertion: Hormone calcitonin has an antagonistic effect to that of parathormone.
Reason: Calcitonin decreases blood calcium level while parathormone increases blood calcium level.

Read the given statements $:$
$(A)$ Hypothyroidism during pregnancy causes defective development and maturation of the growing baby.
$(B)$ Thyroxine does not require a secondary messenger.
$(C)$ Thyroxine plays a major role in the regulation of Basal Metabolic Rate $(BMR)$.
$(D)$ Hypersecretion of thyroxine could cause immunodeficiency.
How many of the above statements are correct?