A The Mantle is cooling down and causing the core to become solid B The mantle is getting heated by the core causing convection
C The asthenosphere is heating up causing fires to occur in the lithosphere.
D the asthenosphere is cooling down causing the more to become solid

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 .

The net force is 100