Answer:
Multicellular organism.
Step-by-step explanation:
Cell is the basic structural and functional unit of all the living organism as all the functions are performed by the cells. Two main types of organism are unicellular and multicellular organism.
Turtles belong to the class reptilia. Turtles are multicellular organism as they are made up of different types off the cell. The organ system level of organization are found in turtles.
Thus, the correct answer is multicellular.