Which disease is related to the thyroxine hormone?

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

On an educational trip to Uttaranchal,Ketki and her friends observe that many local people have swollen necks. Please help Ketki and her friends to find out the solutions to the following questions.
$(a)$ Which probable disease are these people suffering from?
$(b)$ How is it caused?
$(c)$ What effect does this condition have on pregnancy?

High incidence of goitre is seen in the mountainous region because of

Which of the following hormones contains iodine?

The energy-releasing process in body cells is initiated by which of the following glands?