The gland responsible for regulating circadian rhythms is the: MCQ with Answer and Explanation

Explanation:
The pancreas acts as an exocrine gland (secreting digestive enzymes into the duodenum) and an endocrine gland (secreting insulin and glucagon into blood). The liver has metabolic but not major endocrine function, spleen is lymphoid, gall bladder stores bile.

Explanation:
All three processes are part of the nitrogen cycle: fixation (N₂ → NH₃), nitrification (NH₃ → NO₂⁻ → NO₃⁻), and denitrification (NO₃⁻ → N₂).

Explanation:
In plant tissue culture, when an explant (a piece of plant tissue) is placed on a nutrient medium containing specific plant hormones (like auxins and cytokinins), the cells dedifferentiate and undergo rapid, unorganized division to form a mass of cells called a callus. This callus is undifferentiated. Under appropriate hormonal conditions, this callus can then be induced to redifferentiate and form organized structures like shoots and roots (organogenesis) or somatic embryos.