How can the action spectrum be used to assess photosynthetic activity across different wavelengths?

By plotting photosynthetic activity against wavelength, allowing identification of the most effective wavelengths for photosynthesis.

By plotting absorbance against wavelength, allowing identification of the most effective wavelengths for photosynthesis.

By plotting photosynthetic activity against time, allowing identification of the most effective wavelengths for photosynthesis.

By plotting absorbance against time, allowing identification of the most effective wavelengths for photosynthesis.