Which statement about the mass of an electron is correct? A The mass of an electron is equal to the mass of the proton. B The mass of an electron is less than the mass of the proton. с The mass of an electron is equal to the mass of a neutron. D The mass of an electron is greater than the mass of a neutron.​

B because I know it’s b

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 .