Which statement is one of the three parts of cell theory?
a) the smallest living things are single cells, and cells are the functional units of multicellular organisms.
b) there are three types of cells, prokaryotic, eukaryotic plant, and eukaryotic animal.
c) cells make up tissues, tissues make up organs, organs make up systems, systems make up organisms.
d) cell organelles can be membrane-bound or not membrane-bound.
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