The hormone that induces sleep and is secreted by the pineal gland is: MCQ with Answer and Explanation

Explanation:
Xylem is a complex permanent tissue composed of tracheids, vessels, xylem parenchyma, and xylem fibers. It conducts water and dissolved minerals from roots to aerial parts unidirectionally. Phloem transports organic nutrients bidirectionally. Cortex is ground tissue for storage, epidermis provides protection. Xylem vessels are dead at maturity, with lignified walls.

Explanation:
Cuscuta (dodder) is a total stem parasite that wraps around the host plant and absorbs nutrients through haustoria. It lacks chlorophyll and leaves. Mimosa is sensitive plant, Nepenthes is insectivorous, Aloe vera is a succulent. Parasitic plants derive some or all of their nutrition from other living plants. Cuscuta is economically important as a weed.

Explanation:
B lymphocytes differentiate into plasma cells that produce antibodies (immunoglobulins) against specific antigens, providing humoral immunity. T cells mediate cellular immunity, macrophages and neutrophils are phagocytes.