<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 A:<span> Metamorphic rocks</span><span> may display two different grain sizes.</span> :)
The heart of a lazy person pumps blood less efficiently than an athlete who has trained and prepared to achieve a high performance, this can be understood with the example of football players who will play in other countries that have a higher altitude than the country of origin and has to go before to get used to the rarer air
Answer:
Water- from water comes from a variety of sources, including many of the same sources as tap water.
Leather- from rawhide and skins. The most common raw material is cattle hide.
plastic- from cellulose, coal, natural gas, salt and crude oil through a polymerisation or polycondensation process
Explanation:
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