The element that is a key component of the thyroid hormones T₃ and T₄ is: MCQ with Answer and Explanation

Explanation:
Magnesium is the central atom in the porphyrin ring of chlorophyll, essential for light absorption in photosynthesis. Iron is in heme, calcium structural, cobalt in vitamin B₁₂.

Explanation:
Vitamin A is essential for the synthesis of rhodopsin, a visual pigment; its deficiency leads to night blindness, the inability to see in low light conditions. Vitamin B1 (thiamine) is crucial for carbohydrate metabolism; its deficiency causes beriberi, characterized by nerve and heart dysfunction, and muscle weakness. Vitamin C (ascorbic acid) is essential for collagen synthesis; its deficiency causes scurvy, characterized by bleeding gums, loose teeth, and poor wound healing. All three statements are correct.

Explanation:
Minamata disease is a severe neurological syndrome caused by severe mercury poisoning. It was first discovered in Minamata city, Kumamoto prefecture, Japan, in 1956. It was caused by the release of methylmercury in the industrial wastewater from the Chisso Corporation's chemical factory, which contaminated the local bay and the fish and shellfish. People who consumed the contaminated seafood suffered from severe neurological damage, including ataxia, numbness, and muscle weakness.