Give reason.

People living in the hilly areas often have swollen necks.

Swollen Neck:

1. A goiter is indicated by a swollen neck.
2. Iodine insufficiency is common in those who live in hilly terrain, as iodine is essential for maintaining adequate thyroid function.
3. The swelling of the front neck is caused by the enlargement of the thyroid gland.
4. Iodine availability in water and soil is lower in hilly areas, resulting in lower iodine intake.
5. The Himalayas is also known as the 'Goitre belt' in India.