When you catch a baseball, what kind of work do you do, negative or positive? By
catching the baseball, what do you change? Does the basebal gain or lose energy
What kind of energy?

You are negative because you caching

Matter- occupies space and possesses rest massno matter is the opposite

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 .