Typhoid fever is most common in non-industrialized countries. Travelers to Asia, Africa, Eastern Europe, and Latin America are especially at risk. Salmonella typhi bacteria are shed in the urine or stool of infected persons, including chronic carriers. There are no known animal reservoirs for typhoid fever.
Answer:
The fight-or-flight-or-freeze or the fight-flight response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival.
Transmembrane proteins are found in the plasma membrane. Hydrophilic regions are embedded
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within the membrane, and Hydrophobic regions project from both surfaces of the bilayer.
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Approximately 20-80% of the cell membrane is composed of lipids, the rest, is made up of protein. The lipid layer of the membrane gives it flexible and permeable characteristic. While the protein part assists in transport of molecules it needs to survive.<span>
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They are called paleontologists.
The correct answer is: A. A change in a cell's genetic material.
Mutations occur in DNA as a result of mistakes during the DNA replication (when repair mechanisms don’t fix it) or as the result of environmental factors (e.g. UV light). Mutations can have positive impact, by increasing the genetic variation or can have negative effect, causing the diseases or cancer.
