What is the definition of JET STREAM? A. the winds that blow from the west and are in a narrow stream
B. generally, westerly winds concentrated in a relatively narrow and shallow stream up inn upper troposphere of the earth
C the winds that blow and are in a shallow stream in earth
D with that blow around the earth

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 .