Which statement about neutrons is true?
a. neutrons travel around the nucleus of an atom.
b. the number of neutrons in an atom always equals the number of electrons. c. neutrons have less mass than electrons.
or
d. a neutron has no charge.

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 .

Must be negative.substance increases