<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
</span><span>
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>
Answer:
A
Explanation:
The possible number of amino acid residues in the peptide composed entirely of alpha-helical structure and found to contain an integer number of complete turns is 36
Answer:
A galaxy is a collection of millions of stars, while a solar system is a star and the planets around it.
Explanation:
You live in a solar system, we revolve around our sun and so do the other planets making up a solar system
Genetic variation happens when one organism in the population mates with a genetically different organism. Same species, different genetics such as color or height/weight.
