After having one concussion you are more likely to have another — some doctorsestimate you increase your risk up to three times. There are two reasons why your risk increases: carelessness and brain chemistry.
The two words are Genus and Species.
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.
PH meter, which is a device used to measure hydrogen-ion activity in the solution. A PH meter is a voltmeter stuck to a pH electrode and a reference electrode. -maclittleseed
The benefits were more species and also more resources.<span />
