describe the relationship between the age of the rocks and their distance from the mid ocean ridge, please look at the picture to describe their relationship, thank you!

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 .

Ions gain or lose electrons