What happens when a magnet is moved back and forth inside a wire coil? O A. Electric charges begin flowing through the wire.
O B. Electric charges begin flowing through the magnet.
O C. The magnetic force increases.
O D. The magnetic force decreases.

The answer for this question is d. none of these

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 .

Answer(true);