Ami has an old skateboard. She thinks the materials used to make the skateboard should be recycled. Give one disadvantage of recycling the materials in old skateboards.​

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 .

Your answer is a just took the test