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Author Question: In every economic system, choices must be made because resources A) are unlimited, but human ... (Read 88 times) |
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
The first oncogene was discovered in 1970 and was termed SRC (pronounced "SARK").
Malaria was not eliminated in the United States until 1951. The term eliminated means that no new cases arise in a country for 3 years.
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.
Hippocrates noted that blood separates into four differently colored liquids when removed from the body and examined: a pure red liquid mixed with white liquid material with a yellow-colored froth at the top and a black substance that settles underneath; he named these the four humors (for blood, phlegm, yellow bile, and black bile).