AP BIOLOGY

Detailed explanation-1: -Phloem fibers are long, flexible cells that make up the soft fibers used in commerce (such as flax and hemp). Phloem is the biological tissue of vascular plants that transports photosynthesis, a soluble organic compound produced during photosynthesis, to various regions of the plant.

Detailed explanation-2: -The structural elements of phloem include sieve tubes, companion cells, phloem parenchyma and secretory cells. The sieve tube is the conducting element of the phloem. It is formed from a vertical series of elongated cells, interconnected by perforations in their walls in areas known as sieve plates.

Detailed explanation-3: -Phloem is the vascular tissue in charge of transport and distribution of the organic nutrients. The phloem is also a pathway to signaling molecules and has a structural function in the plant body. It is typically composed of three cell types: sieve elements, parenchyma, and sclerenchyma.

Detailed explanation-4: -The bast fibers, which support the tension strength while allowing flexibility of the phloem, are narrow, elongated cells with walls of thick cellulose, hemicellulose and lignin and a narrow lumen (inner cavity).

Detailed explanation-5: -Sieve elements are elongated and function as the basic photosynthate-conducting cell type in the phloem of vascular plants.