A phyloGENETIC tree is not the same thing as a taxonomic tree, which is what Cal described. rRNA and molecular studies are used in phylogenetics to determine relations between species.
1 As the light intensity increases, the rate of photosynthesis increases. 2  However, the rate will not increase beyond a certain level of light intensity. 3  At high light intensities the rate becomes constant, even with further increases in light intensity, there are no increases in the rate.
Most of the time, when the intensity of light is high, you will get a a greater rate of photosynthesis. But, this rate has a limit, and once that limit is hit you can't increase the rate past that limit. Chlorophyll is a green pigment in the chloroplast of the plant cell which absorbs the light.