<span>The immune system is the body's natural defense mechanism against organisms that can cause infection.There are three types of mechanisms:
1. Cellular :</span><span> refers to the recognition and/or killing of virus and virus-infected cells by leukocytes and the production of different soluble factors (cytokines) by these cells when stimulated by virus or virus-infected cells
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2. Structural: </span>barriers and the immune system defend the body<span> against organisms that can cause infection. </span>Natural<span> barriers include the skin, mucous membranes, tears, earwax, mucus, and stomach acid.
3. Chemical: </span><span>Some of these include the low pH of the stomach, which inhibits the growth of pathogens; blood proteins that bind and disrupt bacterial cell membranes; and the process of urination, which flushes pathogens from the urinary tract.
</span><span>antibodies - chemical
tissues lining hollow organs - cellular
phagocytes - cellular
skin - structural
antigen - chemical
leukocytes - cellular</span>
The answer is
<span>Aquifers are underground layers of rocks which contain water and serve as important sources of freshwater. They are located below the water table and in the saturated zone. If an aquifer becomes trapped between two impermeable layer (for example, one below and one above that overlies the aquifer), the pressure act on the aquifer and it can become a confined aquifer.</span>
It becomes D. Groundwater
They have harvested potato's carrots, and more for it was thanksgiving.
Bile helps with digestion
