why is life possible on it?
Due to chemical reactions through the evolution of photosynthesis.
Earth
Chemical reactions led to the first self-replicating molecules about four billion years ago. A half billion years later, the last common ancestor of all current life arose. The evolution of photosynthesis allowed the Sun's energy to be harvested directly by life forms. 
what is the chemical composition of the earth Iron, oxygen, silicon, magnesium, sulphur, nickel, calcium and aluminum to name a few. how did this place get its name? Its developed, via Middle English, from an Old English noun. what is the climatic conditions on it? It can be subdivided into specific latitudinal belts of approximately homogeneous climate. what the construction of it from the inside? It is divided into layers by their chemical or physical (rheological) properties; crust, mantle, liquid outer core and solid inner core. how would you describe the exterior? Of the total surface area of Earth, about 70% s below sea level and covered by ocean water. from the chemical mentioned above, what are the properties of the first one? Magnetic and mechanical properties. at what rate does it liquify? he melting point of iron is experimentally well defined for pressures less than 50 GPa. is it an important element in the food humans eat? Yes, what can happen if they have too much of it? Iron overload disorders, known medically as hemochromatosis. what foods are they found in? Red meat, oysters, lentils, beans, poultry, fish, leaf vegetables, watercress, tofu, chickpeas, black-eyed peas, and blackstrap molasses. what about the second chemical mentioned above, how was it discovered? By heating mercuric oxide and various nitrates. who discovered it? Carl Wilhelm Scheele. any other discoveries made by him? Organic acids like - tartaric, oxalic, uric, lactic, and citric, as well as hydrofluoric, hydrocyanic, and arsenic acids. how did he die? Kidney disease and a disease of the skin. what is the design of the planet mentioned above? The shape is nearly spherical with a small flattening at the poles and bulging around the equator. whats the name of its satellite? The largest artificial satellite is the International Space Station.
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Earth [SEP] Origin of life and evolution
Chemical reactions led to the first self-replicating molecules about four billion years ago. A half billion years later, the last common ancestor of all current life arose. The evolution of photosynthesis allowed the Sun's energy to be harvested directly by life forms. The resultant molecular oxygen () accumulated in the atmosphere and due to interaction with ultraviolet solar radiation, formed a protective ozone layer () in the upper atmosphere. The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes. True multicellular organisms formed as cells within colonies became increasingly specialized. Aided by the absorption of harmful ultraviolet radiation by the ozone layer, life colonized Earth's surface.