AAlbuminous cells and sieve cells
BCompanion cells only
CSieve tubes only
DBoth sieve tubes and companion cells
Answer:
D. Both sieve tubes and companion cells
Read Explanation:
In vascular plants, the living tissue known as phloem carries photosynthates, or soluble organic molecules produced during photosynthesis, to the rest of the plant, particularly the sugar sucrose.
The sieve tube and the associated cells are absent from the phloem of gymnosperms.
Instead, they have sieve cells for the conduction of dietary materials.
The phloem conductive element is the sieve element.
Companion cells are cells that provide "life support" for the sieve's function. Flowering plants have companion cells in their phloem.
They move amino acids and sugar in and out of the sieve components.
The transmembrane proteins are used by the partner cells in the leaf (the tissue of origin) for the active transport of amino acids and sugar.
The conducting component of the phloem is the sieve tube.
It is made up of vertical rows of elongated cells that are joined by holes in their walls in regions referred to as sieve plates