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.
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Natural selection<span> is the differential survival and reproduction of individuals due to differences in </span>phenotype<span>. It is a key mechanism of </span>evolution<span>, the change in </span>heritable traits<span> of a </span>population<span> over time. </span>Charles Darwin<span> popularised the term "natural selection", and compared it with </span>artificial selection<span>.</span>
A drug that affects both divisions of the autonomic system is going to bind to, or block the nicotinic neurotransmitter receptor
A chemical that the body produces to interact with those receptors is called an endogenous chemical, whereas a chemical introduced to the system from outside is an exogenous chemical.
Nicotine is not a drug that is used therapeutically, except for smoking cessation. When it is introduced into the body via products, it has broad effects on the autonomic system.
The nicotinic receptor is found on all autonomic ganglia.
Find out more on receptors at: brainly.com/question/938710
A cytoplasmic reticulum (ER) is mainly referred, or known as an organelle that will appear in eukaryotic cells. Most of the time, you'll hear "cytoplasmic reticulum" be called ER.
Answer: b.We have no other energy source to replace it with
O It is easy, we would be fine with immediately stopping production
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