1. Biological control is the intentional manipulation of natural enemies by humans for the purpose of controlling pests.
2. Mechanical control includes mowing, hoeing, cultivation, and hand pulling.
3. Chemical control is the use of herbicides.
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.
The answer for the above question is the Avascular Necrosis. It occurs as an interruption in the blood flow within the bone resulting in the death of the hematopoietic cells, osteocytes, and marrow fat cells making up the bony structure. It is also called osteonecrosis or ischemic bone necrosis, which occurs when there is loss of blood to the bone, since the bone is a living tissue that needs blood, this interruption of blood supply will result to the death of the bone.
Answer:the action or fact of forming a united whole.
"the work at present lacks cohesion"
Similar:
unity
togetherness
solidarity
bond
sticking together
continuity
coherence
connection
linkage
interrelatedness
PHYSICS
the sticking together of particles of the same substance.
Explanation:
