Answer:
They have helical thickening of lignin in their walls to prevent collapse
Explanation:
the primary function of Xylem and its conducting vessels tracheids is to provide support and tranport water and minerals in plants.
Xylem vessels have layers of dead materials in the walls called LIGNIN. Lignin is a polymer; a very strong, hard materials that stop water passage through it,because it contains dead cells,
Therefore the presence of deposit of these strong impermeable, ligified walls in its walls prevent its collapse during mass flow of water of transpiration pull.
Edema is a condition of abnormally large fluid volume in the circulatory system or in tissues between the body's cells(interstitial <span>spaces).</span>
A. to increase food production
Answer:
The correct answer is B.
Explanation:
Given the baltimore's scheme which used for virus classifications, the most closely related option of virus to the described polio virus with a single stranded RNA in the question would be retroviruses that require a DNA intermediate.
Because much like the single-stranded RNA viruses, the retroviruses do not contain any DNA but they do have an enzyme named reverse transcriptase which they can use to replicate their RNA into the host cells DNA and use the end product for their benefits. So they both work in similar ways.
I hope this answer helps.
