Which statement best compares a multicellular organism to a single-celled organism? a. a multicellular organism has organ systems that interact to carry out life functions, while a single-celled organism carries out life b. a single-celled organism carries out fewer life functions than each cell of a c. a multicellular organism always obtains energy through a process that is different from that used by a single-celled organism. d. the cell of a single-celled organism is always much larger than an individual cell of a m-cellular organism.