AP BIOLOGY

Detailed explanation-1: -It is a living tissue, which is responsible for transporting food and other organic materials. Xylem generally consists of dead cells (parenchyma is the only living cell present in the xylem). Phloem: It is a tubular-shaped, elongated structure having walls with thin sieve tubes.

Detailed explanation-2: -Phloem consists of living cells. The cells that make up the phloem are adapted to their function: Sieve tubes – specialised for transport and have no nuclei .

Detailed explanation-3: -Except for phloem fibres, all phloem components are alive. Because food is transported by active transport, which requires energy, the majority of phloem parts are alive and not dead like Xylem.

Detailed explanation-4: -Xylem is a tissue consisting of dead, hollowed-out cells that form a system of pipes. The walls of xylem cells are lignified (strengthened with a substance called lignin ). This allows the xylem to withstand pressure changes as water moves through the plant.

Detailed explanation-5: -All tissues in the xylem except the xylem parenchyma are dead. Their cytoplasm is highly reduced and they only perform the function of conduction. The xylem tissues also lack cell organelles. Therefore, they are considered dead.