<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>
Answer:
Sea caves
Explanation:
Sea caves is a land form that is formed in a cliff by the action of wave of the ocean or lakes. It is called littoral cave and mainly formed by wave action of a sea which involved the process of mechanical erosion and occur in clogged coast where there is break in the wave or wave action.
1. bony fish
2. cartilaginous fish
3. jawless fish
4. cartilaginous fish
5. bony fish
6. cartilaginous fish
7. Jawless fish
8. bony fish
9. cartilaginous fish
10. bony fish
The answer is chemical energy
Answer:
A. There are fossils of extinct ancestors of horseshoe crabs and the species is still alive today.
Explanation:
C and D have more to do with how it can be a fossil. It is a living fossil because its ancestors have been found in fossils, yet it continues to live today.
