Mainly because our lungs are made to intake air, and if we where to inhale water we would drown. oxygen can only be obtained from the air because our lungs would be able to expell the excess stuff from air easier than in water. hope i helped.
The greater the surface area of a cell, the faster the cell can transport materials across its membrane because there is more area to absorb/excrete materials. We also want the surface area much higher than the volume of a cell. the more volume a cell has the slower the transport of diffusion will be. If the cell is smaller because it has a higher surface area than it does volume. Because of this larger SA:V ratio, smaller cells will transport materials faster.
<span>No they don't,they have to work together for an organ to function.</span>
Mature DNA cells do NOT contain DNA.
