Tadpoles of Frog can be made to grow as giant sized tadpoles, if they are

Options

A. adminstered antithyroid substance like thirourea
B. adiministered large amounts of thyroxine
C. reared on a diet rich in egg yolk
D. reared on a diet rich in both egg yolk and glucose

Answer

a

Explanation

Thyroxine, the perinciple hormone of thyrodi glands, is required, for tisue differentiation and metamophosis (the rapid tansformation from the larval to the adult from)in amphibians so in tis absence of presence of antihyoid substanc, eg. Thiurea, tadpoles or axoloti remain in the larval stage idenfinitely. thiourea is an organic compound of carvon. nitrogen, sulphur and hydrogen with the formula, `CSN_(2)H_(4) or, (NH_(2))_(2) CS`. it is similar to urea. except that oxygen atom is replaced by a sulphur atom.
Antithyroid agents and the thiouracils and mercaptoglyxalines own their activity to the presence of the potentially free thiol group. which by its ready reduction of elementary iodine to iodide ion,
`2R-S-+1+R-S-S-R+2I`
interferes with the iodination of tyrosine in the thyroid protein hence inhibits synthesis of the thyroid hormone.