Which element is essential for the synthesis of the thyroid hormones triiodothyronine (T\(_3\)) and thyroxine (T\(_4\))?

• A. Iodine
• B. Calcium
• C. Iron
• D. Magnesium

Answer: (A)

Verified step by step guidance

1. Understand the role of thyroid hormones: Triiodothyronine (T\(_3\)) and thyroxine (T\(_4\)) are hormones produced by the thyroid gland that regulate metabolism, growth, and development.
2. Identify the chemical composition of T\(_3\) and T\(_4\): Both hormones contain iodine atoms as a critical component. T\(_3\) has three iodine atoms, while T\(_4\) has four iodine atoms.
3. Recognize the essential element: Iodine is required for the synthesis of these hormones because it is incorporated into their structure during hormone production in the thyroid gland.
4. Eliminate incorrect options: Calcium, iron, and magnesium are important for other biological functions but are not involved in the synthesis of thyroid hormones.
5. Conclude that iodine is the correct answer: Iodine is the essential element for the synthesis of thyroid hormones T\(_3\) and T\(_4\).