What is the characteristic pigment that contributes to the blue-green color of cyanobacteria (previously known as blue-green algae)?

✅Explanation:
Phycocyanin is a characteristic pigment found in cyanobacteria that contributes to their distinct blue-green coloration. This pigment is a phycobiliprotein that absorbs light in the orange-red spectrum, complementing the action of chlorophyll a in photosynthesis. Cyanobacteria also contain other pigments like chlorophyll a, but it is the combination of chlorophyll a and phycocyanin that gives them their blue-green appearance.

📌Other Options Explanations:
-b. Xanthophyll: Xanthophylls are yellow pigments found in various photosynthetic organisms.
-c. Beta-carotene (changed from benatin): Beta-carotene, an orange pigment, contributes to the overall color by masking some of the blue from phycocyanin.

🛑 Additional Information::
-Cyanobacteria, also known as blue-green algae, are a group of photosynthetic bacteria that are found in a variety of aquatic and terrestrial environments.
-Cyanobacteria primarily contain phycocyanin and chlorophyll a as their dominant pigments. Chlorophyll b is not a major pigment in cyanobacteria; it is more common in green algae and higher plants.
-Heterocysts are specialized nitrogen-fixing cells found in some filamentous cyanobacteria. They are not characteristic of all genera of cyanobacteria. Only certain genera like Anabaena and Nostoc have heterocysts.
-These specialized cells provide an anaerobic environment necessary for the functioning of the nitrogenase enzyme, which is sensitive to oxygen.