Convection: the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.
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T'belongs to the hydrides, it's a nitrogen hydride.
Water has hydrogen bonds between Hydrogen atoms (that are slightly positive in molecules of water ) and Oxygen atoms (that are slightly negative in molecules of water), so it is necessary more energy to break them down and move water molecules from liquid state to gas.
The answer is: [D]: a reactant.
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