Which disease is caused by the deficiency of thyroxine in adults?

Thyroxin was isolated by

The hormone that controls the basal metabolic rate $(BMR)$ in our body is secreted by:

The hormone responsible for metamorphosis in a tadpole is

$A$ person appears fat,short,and stocky and has a stupid look and protruding tongue due to the hormonal deficiency of:

$A$ pregnant woman delivers a child who suffers from stunted growth,mental retardation,low intelligence quotient $(IQ)$,and abnormal skin. This condition is likely due to: