Answer:

Explanation:
B-cells engulf an antigen by endocytosis.
<u>Endocytosis:</u>
The process by which cell takes up external materials by fusing them with plasma membrane is called endocytosis.
After engulfing the antigen, B-cells become sensitive to the pathogen.
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Hope this helped!
<h3>~AH1807</h3>
Explanation:
It should be in this order from oldest to youngest: 2,1,5,7,9,3,4,8,6.
Since we know 2 is the oldest and once each organism goes extinct it stops being in any samples, we can start at 2 and go through the samples to see where that fossil shows up again and when we find the next sample its in, we pay attention to any new fossils that show up and move onto the next sample with the second fossil in it and so on.
Its d if not im so very sorry
Nitrogen wastes I think :)
Answer:
The generation of nitric oxide is done by almost every kind of cell present in the human body, it is one of the essential constituents that plays an important function in maintaining proper health of blood vessels. The nitric oxide acts as a vasodilator, that is, it relaxes the blood vessels' inner muscles, thus making the blood vessels to broaden.
Therefore it can be concluded that nitric oxide enhances the flow of blood and thus reduces the blood pressure. In this manner, nitric oxide helps in tackling the symptoms of conditions like angina.
At the molecular level. the activation of guanylyl cyclase is done by nitric oxide, which further catalyzes the production of cGMP. This cGMP further functions as an intracellular messenger in a pathway that results in the relaxation of the smooth muscles.