Q.

Which statement is not true about thyroxine

1 Thyroxine regulates the basal metabolism of our body.  
2 Iodine is an important component required for synthesis of thyroxine.  
3 Under secretion of thyroxine causes simple goitre.  
4 Iron is essential for synthesis of thyroxine.  

Ans.

(4)

Iodine, not iron, is required for the synthesis of thyroxine. It controls the glucose, protein, and fat metabolism of the body. The thyroid gland produces thyroxine, which is also known as thyroid hormone.