Answer:
Cells are in the main small. The surface area has to be large enough in relation to the volume of cytoplasm that contains mitochondria requiring adequate respiratory substrate (such as glucose) and oxygen (at least in aerobes) in order to generate ATP (adenosine tri phosphate) for the cell’s energy needs.
It is imperative for cells to get oxygen supplied fast enough and carbon dioxide removed fast enough. This happens by diffusion through the cell membrane surrounding it.
Step-by-step explanation: