Deficiency of iodine cause a disease called goitre. It occurs due to lack of thyroxine production by the thyroid gland.

Symptoms include:

a) Swollen neck

b) Hampered metabolism

c) Coughing

d) Difficulty in breathing.

Explanation: Iodised Salt is Necessary because iodine mineral is a necessary part of thyroxine hormone secreted by the thyroid gland. Thyroxine helps in regulating the metabolism of carbohydrates, fats, and proteins. It is responsible for governing the rate of metabolism in the body.