Pigments such as chlorophyll are needed because they capture light energy to be used for photosynthesis.
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Pigments such as chlorophyll absorb certain wavelengths of light. There are two forms of chlorophyll used by plants: chlorophyll a and chlorophyll b. These two types absorb light well within the blue-violet and red portions of the visible spectrum but do not absorb light in the green part of the spectrum; therefore, chlorophyll gives plants their green color because chlorophyll reflects green light.