The of the wavelengths of a visual stimulus determines the perceived saturation, or richness, of the stimulus.

The purity of the wavelength of a visual stimulus determines the perceived saturation, or richness, of the stimulus. Wavelength is the distance from the peak of one wave to the next. Stimulus is a change in the environment and the reaction of the organism to it is the response. 

The right answer is b hydrogen bonds!

Cbecause it is the only one describing a habitat