Answer:
1. hydrogen Nitrogen Lead Mercury
2. Phytoplankton
3. About 71 percent of the Earth's surface is water-covered, and the oceans hold about 96.5 percent of all Earth's water. Water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers, and even in you and your dog.
Step-by-step explanation:
Did you know that more than half of the oxygen on earth is produced by these tiny one-celled plants in the surface of the ocean called phytoplankton?
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