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A community is a group of animals that coexist in the same environment
The water cycle is a parameter of the hydrosphere that always remains constant. Life on Earth and its sustenance is possible because of this cycle. The continuous evaporation, condensation, and precipitation of water provides for the many processes involved in Earth's natural surroundings. Without the water cycle, life would cease to exist.
Different types of blood contact different kinds of antigens and antibodies. For example, Type A blood has A antigens and B antibodies, antibodies being the thing that fights B antigens. Type B blood has B antigens and A antibodies. So if someone with type B gets transfused with Type A blood, the person's antibodies will attack the new blood.