Which pigment is essential for plants to absorb sunlight for photosynthesis?

Chlorophyll is the pigment that plays a crucial role in photosynthesis by absorbing sunlight. Located primarily in the chloroplasts of plant cells, chlorophyll primarily captures light energy in the blue and red wavelengths, which is essential for converting carbon dioxide and water into glucose and oxygen. This process is vital for the plant's energy needs and growth, making chlorophyll indispensable for plants to synthesize their food using sunlight.

While other pigments like xanthophyll and carotene also contribute to light absorption and can protect chlorophyll from damage, they do not serve as the primary pigment responsible for the photosynthesis process. Bilirubin, on the other hand, is a breakdown product of hemoglobin and is not involved in photosynthesis in plants. Thus, chlorophyll is the key pigment that enables plants to effectively harness solar energy, making it essential for their survival and growth.