The hormone responsible for metamorphosis in a tadpole is

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?

How does the activity of growth hormone relate to thyroxine?

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

Which are the symptoms of exophthalmic goitre?

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