What is true about energy in an ordinary chemical reaction? energy is
created during the reaction.
destroyed if there is an explosion.
not created or destroyed.
used up by the reaction.

Ithink its solid. hope this

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 .