If greenhouse gases in the atmosphere act like a blanket around the Earth, how is this "blanket" being changed by human activities? It is getting thinner and keeping the Earth cooler. It is getting thicker and keeping the Earth cooler. It is getting thicker and keeping the Earth warmer. It is getting thinner and keeping the Earth warmer.

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 formula is (nh4)2co3