Why cell size remain small even though organism size is large

Cell size is limited by a cell's surface area to volume ratio. A smaller cell is more effective and transporting materials, including waste products, than a larger cell. Cells come in many different shapes. A cell's function is determined, in part, by its shape.

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus

c. is the correct answer