Answer:
A. Natural killer (NK) cells are activated in response to interferons or macrophage and Major histocompatibility complex (MHC) and allows direct apoptosis of virus.
Viruses can invade NK cells by inhibiting MHC from reaching the cell surface. Using stimulating the inhibitory receptors and disrupting the activating receptors, viruses can avoid NK cells. MHC act as a ligand of inhibitory receptor, and when bind with inhibitory receptor allows damage to NK cells.
So, if i would be a virus i will use inhibitory receptors stimulation to avoid NK cells.
B. Bacteria are killed by phagocytic immune cell macrophages by engulfing them.
Bacteria avoid macrophages by escaping from phagosome before the lysosome fuses as lysosomal chemical kill the bacteria and some bacteria prevent acidification of the phagosome.
C. Parasites can avoid macrophages by modulating the host's cell cytoskeleton to block proper phagocytosis.
D. Bacteria can avoid dendritic cells by avoiding lysosomal degradation and prevent antigen presentation on MHC molecules that will modulate the entrance to DCs.
E. B cells are responsible for producing antibodies. Activation of B-cell depends on positive and negative signals transmitted through the B-cell receptor (BCR), so genetic polymorphisms and mutations affects the positive and negative signals. If mutation is done showing negative signal, B cell will not the activate and no antibodies will produce.
Answer:
Wind, Insects/animals
Explanation:
Pollination is the process by which pollen grains move from the anther(male part) to the stigma( female part).
Pollination by wind is usually made possible with flowers who have feathery stigma. The feathery stigma is easily swayed by the wind which makes it possible for it to catch pollen grains in the air.
Pollination by insects/animals is made
Possible by a form of attraction which is usually in the form of conspicuous petals and a good odor. These features attracts the insects/animals to the flowers.
Answer:
44- object 2
45- objects 1 and 4
Explanation:
44- object 2 push force is higher one the left then on the right
45- object 1 cancel eachoher because they have the same push force as eachoher and object 4 don't move at all because they don't have any push force on either side
The statement that best describes the difference is ; The substance with the lower pH has 1000 times as many hydrogen ions per volume of water. ( D )
Given that the substance have pH ; 3 and 6
To prove the statement above we will make use of the pH formula
pH = -log(H⁺)
<u>for substance with </u><u>pH = 3</u><u> </u>
3 = - log(H⁺)
H⁺ ( hydrogen ions ) = 10⁻³
<u>for substance with </u><u>pH = 6</u>
6 = - log(H⁺)
H⁺ ( hydrogen ions ) = 10⁻⁶
Hence we can state that the substance with the lower pH has 1000 times as many hydrogen ions per volume of water
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Answer:
here is the answer hope it will help you
