Which of the following is referred to as the "suicide gland"?

Which endocrine gland stores its secretion in the extracellular space before discharging it into the blood?

$A$ toxic agent present in food which interferes with thyroxine synthesis leads to the development of:

$BMR$ is controlled 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 $:-$

Which substance should be added to water to accelerate the process of metamorphosis in tadpoles?