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Vaccines prevent between 2.5 and 4 million deaths every year.
A seasonal flu vaccine is the best way to reduce the chances you will get seasonal influenza and spread it to others.
The Romans did not use numerals to indicate fractions but instead used words to indicate parts of a whole.
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.
Pope Sylvester II tried to introduce Arabic numbers into Europe between the years 999 and 1003, but their use did not catch on for a few more centuries, and Roman numerals continued to be the primary number system.

