Which change would increase the pressure exerted by a gas? removing gas molecules from the container
transferring the gas to a larger container
raising the temperature of the gas
reducing the force of the molecules hitting the container

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 .