The stomata and their guard cells allows this happen.
Stomata is like a hole or gap on a leaf, most of them are present in a bottom side of the leaf, since waxy cuticle is not present over there. And 2 guard cells make up a stomata.
Guard cells are able to control the size of the stomata, depending on the situation. For example, the guard cells close up during day time because a lot of sunlight may cause more water loss.
In conclusion, guard cells and the stomata are the main structures that allow carbon dioxide and oxygen (water too) diffuse in and out of leaves.
Answer:
Diffusion occurs when there is movement of minerals from an area of higher to lower concentration, till equilibrium is obtained.
Whereas Osmosis is the movement of solvents rather then the solute, from a solution of lower to a solution of higher concentration with the help of semipermeable membrane.
Explanation:
Diffusion is the movement of substances from area of higher concentration to an area of lower concentration of minerals, which mainly results in animal cells. Whether solute or solvent, diffusion occurs for both. Diffusion does not requires any semi permeable membrane. Diffusion occur in all state of matter, that solid, liquid and gas, whereas osmosis occurs only in liquid state. Osmosis requires semipermeable membrane and rate of which is related to concentration of solute dissolution in solvent medium. Only movement of solvent medium takes place. Classical example of osmosis is exhibited by cell membranes of animal cells. On the other hand diffusion is the spreading of perfume or fragrances to the external air.
It is important because you need vitamins and minerals from them e.g. Scurvy no vitamin c