Your analysis of your evidence is the most important part of your response essay. It is important that you do not simply restate your evidence or your thesis when constructing analysis. Instead, you should look to explain how the author's technique or use of a character, for example, adds to the theme conveyed.
Land plants (and plants in the ocean, called algae) have a lot of chlorophyll-a pigment because it is essential to photosynthesis, but they also have other pigments, called accessory pigments, that help them absorb light.
Chlorophyll is the pigment that gives plants and algae their green color. Plants use chlorophyll to trap light needed for photosynthesis (1). The basic structure of chlorophyll is a porphyrin ring similar to that of heme in hemoglobin, although the central atom in chlorophyll is magnesium instead of iron.