NEET BIOLOGY

Detailed explanation-1: -Secondary xylem (wood) and phloem are the inner and outer derivative products of the vascular cambium. Xylem is mainly comprised with dead cells with thickened cell walls rich in cellulose, hemicelluloses, and lignin and responsible for providing mechanical support and conducting water and minerals for the plant.

Detailed explanation-2: -The inner layer of secondary xylem forms the heartwood and the outer layer forms the sapwood. The sapwood contains young layers of the tree and it performs water conduction in large woody trees. Thus, the common name of wood is called secondary xylem.

Detailed explanation-3: -toward the inside are called secondary xylem, or wood, and those formed toward the outside of the cambium are called secondary phloem. The bark and the wood together constitute the secondary plant body of the tree. The woody vascular tissue provides both longitudinal and transverse movement for carbohydrates and water.

Detailed explanation-4: -Because we are considering the secondary growth, we refer to the xylem produced by the vascular cambium as secondary xylem (wood). As the secondary xylem accumulates from one growing season to the next, the stem grows in diameter (this is called girth).

Detailed explanation-5: -Wood is a product of secondary growth in a plant. This secondary growth arises from the vascular cambium, which creates secondary vascular bundles (i.e. secondary xylem and phloem) after initial cell elongation and growth of a plant has ceased. Wood is mainly composed of the secondary phloem.