<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>
Maybe the paper A has more evidence and more detail than aper b
When molecules are being transported opposite to the molecules concentration gradient.
Hope i helped!
The requirement of energy makes an organism’s cell make up different from the cell makeup of an inanimate object.
All living things require energy from food in order to function properly. The energy from food is used through the metabolic processes.
Animal cells<span> and plant </span>cells<span> can form tissues, such as muscle tissue in animals. A living tissue is made from a </span>group<span> of </span>cells<span> with a </span>similar<span>structure and </span>function<span>, which all </span>work together<span> to do a particular job. Here are some examples of tissues: muscle. the lining of the intestine. the lining of the lungs.</span>
