Answer: Accessory pigments
Step-by-step explanation:
The wide range of colors in algae is produced by the accessory pigments. These compounds in the plants assist in the absorption of the light during the process of photosynthesis.
They are helpers and assist the chlorophyll in absorption of light. Red algae has an accessory pigment known as phycoerythrin as the accessory pigment which absorbs red colored light which gives red algae red color.
This does not means that algae does not have chlorophyll, it does have but the pigments mass the effect of chlorophyll.