Which of the following disorders is related to the thyroid gland?

The rate of metamorphosis is increased by .....

Select the answer which correctly matches the endocrine gland with the hormone it secretes and its function/deficiency symptom.

Thyroxine is secreted 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 $:-$

Why is $Thyroxine$ considered a hormone and not an enzyme?