Which best explains how objects become electrically charged? a. protons are rubbed from one object to another. b. a magnet rubbed on a rope electrically charges the object. c. charged atoms are rubbed from one object to another. d. electrons are transferred from one object to another.

Protons are rubbed from one object to another

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 .