Dela is helping his Aunt Starr on an archeological dig. His aunt gives him a bucket containing sand, rocks, and artifacts. What
is the best way for Dela to separate the sand from the other
materials?

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 .