Baking soda is often used in experiments to neutralize vinegar. in the picture above, the beaker on the left contains a solution
of vinegar. what can you conclude about the picture on the right?

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 .

So3 that’s what i think

A. is your answer.  hope this