As it dissolves a large number of solid, liquid and gaseous substances it's called a universal solvent. It's important for living thing because all of them depend on water to survive. For example, many organisms live in the water and they find some of the nutrients that are necessary for live dissolved in water - gases included.
Grease is nonpolar. It is made up of lengthy hydrocarbon chains attached to glycerol (triacylglycerols). Because of this property, nonpolar solvents, such as tetrachloroethylene, can get grease out of clothes. This solvent acts by dissolving the grease, thereby removing it from clothes without leaving any residue.
The lewis structure is helpful in showing how the bonding between atoms of a molecule are. The lewis structure of ammonia would be that the nitrogen atom will share three pairs of electron with the three hydrogen atoms leaving nitrogen to have 1 lone pair.<span />
I believe the correct answer from the choices listed above is the fifth option. Of the following , the strong electrolyte would be NH4NO3. NH4NO3<span> is a salt and completely dissociates in aqueous solution. Hope this answers the question. Have a nice day.</span>