Achemical reaction in which compounds break up into simpler constituents is a reaction.
a. double replacement
b. substitution
c. decomposition
d. combination

C) Decomposition. Double replacement would be AB + CD = AD + BC, substitution is AB + C = CB + A, and combination is A + B = AB

The teacher is mostly talking about the distillation of a mixture

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 .