Question

Seaweeds are the main source of:

• A. Iron
• B. Chlorine
• C. Bromine
• D. Iodine

Hint:

This mineral is needed by the thyroid gland to make its hormones.

Answer 1

The Correct Option is D

Step 1: Understanding the Question.
The question asks which mineral seaweeds are best known to supply in large amounts.

Step 2: Key Concept.
Seaweeds grow in the sea and take up minerals dissolved in seawater. They are able to pull in and store iodine from the water at levels much higher than most land plants can, which makes them a rich natural source of iodine. Iodine is needed by the thyroid gland to make hormones that control the body's metabolism.

Step 3: Detailed Explanation.
Because of this iodine-storing ability, seaweed and kelp have long been used as a food source of iodine, and iodine was first extracted commercially from seaweed ash.
Iron is present in seaweed only in small amounts and is not what seaweed is known for.
Chlorine is common in seawater as part of ordinary salt, but it is not the mineral linked to seaweed as a special dietary source.
Bromine also occurs in seawater in trace amounts, but seaweed is not recognised as its main dietary source.

Step 4: Final Answer.
Seaweeds are the main source of iodine, so option (D) is correct.