AP BIOLOGY

Detailed explanation-1: -Sieve tube elements, parenchyma, sclerenchyma (bast fibres ) and companion cells are components of phloem.

Detailed explanation-2: -Phloem is composed of various specialized cells called sieve elements, phloem fibres, and phloem parenchyma cells.

Detailed explanation-3: -It has four elements, namely, companion cells, sieve tubes, phloem parenchyma, and phloem fibres.

Detailed explanation-4: -The different elements of phloem include sieve tubes, companion cells, and phloem parenchyma and phloem fibres.

Detailed explanation-5: -The phloem is composed of three types of cells – the conducting cells, the parenchyma cells and the supportive cells. The conducting cells, also called sieve elements, are composed of columns of sieve tube cells that have perforations in their lateral walls and that helps in the conduction of food throughout the plant.