Which of the following diseases is associated with the thyroid gland?

Iodine deficiency causes:

Metamorphosis in amphibians can be accelerated by

$A$ pregnant lady delivers a baby who suffers from stunted growth,mental retardation,low intelligence quotient and abnormal skin. This is the result of $:-$

The hormone responsible for metamorphosis in a tadpole is:

Calcitonin lowers the calcium level in the blood. This is secreted by