Please help me i need to answers this questions for homework please help!!! ​

1. Nitrogen Hydrogen 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.

4.Water can be used for direct and indirect purposes. Direct purposes include bathing, drinking, and cooking, while examples of indirect purposes are the use of water in processing wood to make paper and in producing steel for automobiles. The bulk of the world's water use is for agriculture, industry, and electricity.  

sorry i could not answered all of them but hope it helps

temperatures get warmer — and heatwaves are more common. nothing says summer like warm weather. this rise in temperatures is caused by the tilt of the earth's axis. our planet doesn't sit perfectly straight as it spins — it has a slight lean of approximately 23.5 degrees with respect to the sun, called the axial tilt.

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