Which of the following is a correct match between the hormone and its function? MCQ with Answer and Explanation

Explanation:
PCR, invented by Kary Mullis, allows exponential amplification of a specific DNA segment using a thermostable DNA polymerase (Taq polymerase), primers, and thermal cycling. Gel electrophoresis separates DNA fragments, Southern blotting detects specific sequences, DNA sequencing determines the order of bases. PCR is widely used in diagnostics, forensics, and research.

Explanation:
Iodine is essential for the synthesis of thyroid hormones T₃ and T₄. Deficiency causes hypothyroidism and goiter (enlarged thyroid gland). Iodized salt is a preventive measure.

Explanation:
Double circulation (pulmonary and systemic) with a four-chambered heart keeps oxygenated and deoxygenated blood separate, increasing efficiency. R correctly explains A.