The defense system of the human body is made up of entire organs and vessel systems like the lymph vessels, but also of individual cells and proteins. The inner and outer surfaces of the body are the first barriers against pathogens (germs). These surfaces include the skin and all mucous membranes, which form a kind of mechanical protective wall.
Several things support this protective wall:
<span><span>- The body’s own antibacterial substances can disable different pathogens from the environment at an early stage. A certain enzyme found in saliva, the airways and tear fluid destroys the cell walls of bacteria.
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- Many pathogens that are breathed in get stuck to mucus in the bronchi and are then moved out of the airways by hair-like structures called cilia.
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- Most pathogens that enter the body together with food are usually stopped by stomach acid.
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- Normal flora, harmless bacteria that reside on the skin and many mucous membranes in the body, also help to protect the body.</span></span>
The cough and sneeze reflex can also help to remove pathogens.
Hope this helps (:
Nuclear división in eukaryotic cells that occurs when a parent cell divides to produce two identical daughter cells .
Viruses are the exception too the cell theory, but they have some characteristics of living things. What is one of these characteristics?
Genetic material.
Answer:
O silicon (Si)
Explanation:
-Valence electrons are electrons of the outermost shell which can participate in chemical bonding. ... -As in silicon, four electrons are present in the outermost shell, so silicon has Four valence electrons.
