In which of these systems is the entropy decreasing?
a. air escaping from a tire
b. snow melting
c. salt dissolving in water
d. a gas condensing to a liquid

"A gas condensing to a liquid" is the one system among the following choices given in the question where the entropy is decreasing. The correct option among all the options that are given in the question is the fourth option or option "D". I hope that this is the answer that has come to your desired help.

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 .