Which is the role of the gall bladder? A. to provide physical digestion
B. to store the liquid produced by the liver
C. to make the liquid that is stored in the liver
D. to decrease the chemical digestion

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 .

Replicate prove reliability and validity

Your awser would be a acetone