What are examples of variations within groups of molecules being helpful?

The different types of pigments used for absorption in photosynthesis (chlorophyll a, chlorophyll b, and β-carotene) absorb different wavelengths. This allows the organism to absorb energy from a wider range of wavelengths.

The diverse range of antibodies allows the body to recognize an almost infinite number of antigens. This way, the body can respond to any viral disease with antibodies.