<span>Humans add greatly to the carbon cycle by "</span>exhalation of carbon<span> dioxide, the burning of fossil fuels, deforestation and other poor agricultural practices."
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Light energy can be converted to heat energy. Electrical energy can be converted to mechanical energy, light energy, heat energy, etc. Chemical energy can be converted to electrical energy.
Answer: creating an ozone layer to shield life from UV rays
Cynobacteria or blue green algae is the strain of bacteria, which was able to produce oxygen in the primitive earth as a result of photosynthesis. The abundance of oxygen in the atmosphere formed the ozone layer in the upper atmospheric layers, these layers are protective enough to provide a shield against the harmful UV radiations incident on earth coming from the sun.
