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Vaccines cause herd immunity. If the majority of people in a community have been vaccinated against a disease, an unvaccinated person is less likely to get the disease since others are less likely to become sick from it and spread the disease.
Congestive heart failure is a serious disorder that carries a reduced life expectancy. Heart failure is usually a chronic illness, and it may worsen with infection or other physical stressors.
When blood is deoxygenated and flowing back to the heart through the veins, it is dark reddish-blue in color. Blood in the arteries that is oxygenated and flowing out to the body is bright red. Whereas arterial blood comes out in spurts, venous blood flows.
Most fungi that pathogenically affect humans live in soil. If a person is not healthy, has an open wound, or is immunocompromised, a fungal infection can be very aggressive.
Egg cells are about the size of a grain of sand. They are formed inside of a female's ovaries before she is even born.