Answer:
Looking for light
Explanation:
Since plants require sunlight in order to produce light, they need to be exposed to it. Now, since there are other plants attempting to do the same they have to grow higher so they don't get put in the others shadow and possibly die due to lack of sunlight.
Oxygen molecules diffuse fast because the main gas in a cell in Carbon Dioxide its like if it was 99.9 percent carbon that .1 percent is oxygen and carbon dioxide being what it is. Automatically overrides the amount of oxygen. Basically it is nonpolar