Assertion (A): Restriction enzymes are used in recombinant DNA technology. Reason (R): They cut DNA at specific recognition sequences. MCQ with Answer and Explanation

Explanation:
Vernalization is the process by which many plants, particularly biennials and winter annuals (like winter wheat, cabbage, and carrots), require exposure to a prolonged period of low temperature (cold treatment) before they can initiate flowering. This prevents the plant from flowering in the autumn, ensuring it survives the winter and flowers in the spring or summer. The cold stimulus is perceived by the apical meristem or the germinating seed.

Explanation:
The pancreas functions as an exocrine gland (secreting digestive enzymes into the duodenum via the pancreatic duct) and an endocrine gland (secreting insulin, glucagon, somatostatin from the islets of Langerhans into the blood). Thyroid, pituitary, and adrenals are purely endocrine.

Explanation:
The central vacuole occupies a large volume of a mature plant cell and stores water, creating turgor pressure against the cell wall, which maintains cell rigidity and plant structure. The cell wall provides mechanical support but turgor pressure generated by the vacuole is essential for maintaining turgidity, especially in herbaceous plants.