Which of these statements explains a key difference between unicellular and multicellular organisms?. Single choice. Only multicellular organisms can photosynthesize.
The cells of unicellular organisms are much smaller than the cells of multicellular organisms.
multicellular organisms are more complex

Multicellular organisms are more complex.

Explanation:

classical republicanism, also known as civic humanism, is a form of republicanism  developed in the renaissance inspired by the governmental forms and writings of  classical  antiquity, especially such  classical  writers as aristotle, polybius, and cicero.