Which are primary nitrogen-fixing organisms in the ocean? a. Archaea b. Eukarya c. Cyanobacteria d. Dinoflagellates e. Copepod
What is the largest biogeochemical cycle? a. carbon cycle b. nitrogen cycle c. phosphorus cycle d. silicon cycle e. ferrous cycle
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Vaccines prevent between 2.5 and 4 million deaths every year.
The familiar sounds of your heart are made by the heart's valves as they open and close.
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
The first war in which wide-scale use of anesthetics occurred was the Civil War, and 80% of all wounds were in the extremities.
The most destructive flu epidemic of all times in recorded history occurred in 1918, with approximately 20 million deaths worldwide.
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