Identify the correct statement about the human reproductive system: MCQ with Answer and Explanation

Explanation:
Gymnosperms have naked seeds on cones, not in an ovary; hence no fruit. Angiosperms have enclosed seeds. R correctly explains A.

Explanation:
The adrenal medulla produces adrenaline and noradrenaline; cortisol is produced by the adrenal cortex. So B is incorrect.

Explanation:
In 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty conducted a landmark experiment building on Griffith's transformation experiment. They purified various macromolecules (DNA, RNA, proteins, lipids) from the virulent S strain of Streptococcus pneumoniae and tested which one could transform the non-virulent R strain into the virulent form. They found that only DNA could cause transformation, and this activity was destroyed by DNase but not by RNase or proteases. This provided the first strong, direct evidence that DNA, not protein, is the genetic material.