Which of the following chemical reactions is an example of an endothermic reaction?
A. Making ice cubes from liquid water
B. The combustion of gasoline
C. The evaporation of water
O
D. Burning a candle

Icant see the pictures 

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .

Molarity is moles of solute over liters of solution. idk if that is what you are talking about, but you can convert moles of solute to grams of solute using dimensional analyzes by using molar mass found on the periodic table.