Earth is a beautiful planet that revolves around a star called Sun, which is located in one of the arms of our Milky Way Galaxy. It is the only planet known to support life in the Solar System. Humans are the most intelligent civilization on this planet. It's blue when seen from space. Recently, Earth 29 spacecraft was able to land on this planet, after 28 unsuccessful landings of Earth series of spacecrafts. We were able to learn many things about humans, most important of these was the most spoken language of them, which they call English. According to experts, humans are not yet ready to know about our existence. It can take about 1 or 2 more centuries, until they are ready to know about us.
Energy convention: Convection is the motion of a fluid driven by temperature differences across that fluid. When a fluid is heated, the region in closest contact with the heat source becomes less dense due to increased kinetic energy in the particles. Convection is one of the fundamental ways that heat is transferred
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<u>Density</u> – The amount of matter in a given space. In scientific terms, density is the amount of mass in a unit of volume.
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The amount of matter in a given amount of space is known as the <u>Density.</u>
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2 - Human refuse to stop polluting.
All other three are attempting to attack the problem of pollution.
