............ support the process of red blood cells formation.

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A):$ During pregnancy,the level of thyroxine is increased in the maternal blood.
Reason $(R):$ Pregnancy is characterised by metabolic changes in the mother.
In the light of the above statements,choose the most appropriate answer from the options given below:

$A$ toxic substance present in food prevents the synthesis of thyroxine. As a result,which of the following will occur?

Thyroxine is secreted by

The two lobes of the thyroid gland are connected by a thin flap of connective tissue called the.....

Which of the following hormones is a derivative of an amino acid?