Neutrons.
Not sure if you need a full explanation but let me know if you do :]
Answer
The Density of a substance can change if its location changes.
Explanation
All the statements are TRUE except
The Density of a substance can change if its location changes.
This is because density is an intensive property, that is regardless of the object's shape, size, or quantity, the density of that substance will always be the same. Even if you cut the object into a million pieces, they would still each have the same density.
Therefore, the statement that is FALSE is
The Density of a substance can change if its location changes.
The burning of fossil fuels like coal, natural gas etc... leads to the emmission of carbondioxide which is a green house gas and leads to the increase of heat in the atmosphere. This results in greenhouse effect.
Answer : Option 4) 
Explanation : is the only sample of matter which can be classified as a solution. As the solution can be defined as a liquid mixture which contains a minor component (the solute) that is uniformly distributed within the major component (the solvent).
In this case, the solute is 
which is dissolved in water which acts as an solvent. Also, it has a subscript which is aq. which means aqueous, is often given to the solution in which the solvent is water.
Therefore, is the correct answer.
