Newton’s 3rd Law states… a. Objects in motion stay in motion and objects at rest stay at rest
b. Force is equal to mass times acceleration
c. For each action there is an equal and opposite reaction

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 .

The answer is nitrogen-containing bases