GIVING 20 POINTS!! Which of the following is the lowest level in the hierarchy of the organization of living things?

Atoms
Compounds
Organ systems
Tissues

It’s the energy source of stars

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 .