To prove Hess' theory of seafloor spreading, divers and submarine drones have gone into ridges and have discovered the following . a) the trenches are moving
b) marine life
c) molten material at the bottom of the trench, meaning new rock formation
d) molten material far away from the trench meaning old rock formation

Because it was a dramatically big guy

What are the options? i can you if you give them.

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 .