The thyroid gland produces a substance containing iodine that helps regulate growth.
Goiter is an enlargement of the thyroid gland
caused by a lack of iodine in the diet. Goiter
is uncommon in coastal areas where people
eat seafood that contains a form of iodine.
It is more common inland, where people
eat food that has been grown in soil
lacking iodine.
Which phrase restates the cause of the
disease goiter, as given in the passage?
(1) eating too much fish
(2) eating too little of foods high in iodine
(3) exposure to a bacterium found in iodine
(4) fertilizing the soil with iodine
(5) inheriting a defective thyroid gene