Organize the parts of the body system from most basic to most complex
according to the levels of organization in a multi-cellular organism.
a. Human being central nervous system brain & nerve tissue & neurons (brain cell)
b. Neurons (brain cell) brain & nerve tissue
central nervous system & human being
c. Neurons (brain cell) & nerve tissue brain central nervous system human being
d. Nerve tissue central nervous system & neurons (brain cell) & brain & human being
