The correct answer is B. unicellular.
Dinoflagellates are unicellular or multicellular, producers, and autotrophs, and apple trees are multicellular, producers, and autotrophs. All plants have numerous cells in them, so they can never be unicellular. The remaining characteristics they share with less complex organisms such as dinoflagellates.
The ability of an organism to maintain internal conditions is called <em>C homeostasis </em>
