How do plants breathe under water?
The world has had plants for many hundred million years. But let’s use our imaginations to speed up this long story into six days. From Monday until. Friday, all plants lived in the sea and used oxygen from the water. On Saturday morning a few came on land and learned to use the oxygen in the air. All the lush and lovely land plants are descended from ancestors that lived in the sea. The plant world used oxygen and other gases in the water long before it used the gases of the air. The living cells in a plant must exchange gases with the outside world, but a plant does not breathe by puffing in and out. Nature has a special postal service to deliver the gases a plant needs and collect up its waste gases. This busy postal service is called diffusion and it works in both air and h*ater. You can see how diffusion works when you watch a puff of pearly smoke spread through the air of a room: Gas molecules are too small for our eyes to see, but they spread by diffusion, seeping through walls
