For a multicellular organism, which statement about cellular activity is correct? All cells of the organism carry out most of the major functions of life. All cells of the organism carry out most of the major functions of life. Brain and heart cells are the only cells that carry out most of the major functions of life. Brain and heart cells are the only cells that carry out most of the major functions of life. Only gametes (sex cells) carry out all of the major functions of life. Only gametes (sex cells) carry out all of the major functions of life. Only somatic (body) cells carry out all of the major functions of life.