So how did Earth end up with an atmosphere made up of roughly 21 percent of the stuff? The answer is tiny organisms known as cyanobacteria, or blue-green algae. These microbes conduct photosynthesis: using sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen.
Photosynthesis: Is the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.
the correct answers are People depend on the atmosphere for the air they breathe. It screens out the sun's ultraviolet rays. Warm air has more moisture content than cool air.
The place where two plates come together, or converge, is called a convergent boundary. When two plates converge, the result is called a collision. When two plates collide, the density of the plates determines which one comes out on top.
