Which of the following pieces of evidence suggests there was a chemical change? Change in color
Change in shape
Change in size
Change in state

What does that mean you dum bum

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 .