In genetics, the 'Lac operon' is an example of a(n): MCQ with Answer and Explanation

Explanation:
Potato is a modified stem (tuber) that stores starch. The 'eyes' on a potato are axillary buds, confirming it as a stem. Sweet potato is a modified root (tuberous root), carrot is a taproot, radish is a modified root. Other modified stems include ginger (rhizome), onion (bulb, though bulb is a modified stem with fleshy leaf bases), and garlic.

Explanation:
While the Blood-Brain Barrier (BBB) protects most of the brain, there are specific areas where the BBB is absent or highly permeable. These are the circumventricular organs (CVOs), which are located around the third and fourth ventricles. Because they lack a typical BBB, they can directly sample the chemical composition of the blood and cerebrospinal fluid. This is essential for their functions, which include neuroendocrine regulation (e.g., the area postrema for vomiting, the organum vasculosum of the lamina terminalis for osmoregulation, and the median eminence for hormone release).

Explanation:
Respiration occurs 24/7, while photosynthesis only in light. The statement implies they alternate, which is false. R is true: photosynthesis needs light, respiration is continuous. So A is false, R true.