Now suppose that light in the yellow range of wavelengths (approximately 577 nm to 597 nm) enters the eye and strikes the retina. Light with these wavelengths would activate both the green and the red cones of the retina.
Brewer's yeast is a kind of yeast that is a by-product of brewing beer. Dietary supplements containing brewer's yeast often contain non-living, dried yeast. People use brewerâs yeast to make medicine. Brewer's yeast is used for diarrhea, the common cold and other upper respiratory tract infections, influenza, swine flu, loss of appetite, acne, premenstrual syndrome (PMS), recurring boils on the skin (furunculosis), and type 2 diabetes. It has also been used as a source of B vitamins, chromium, and protein.
The most important ingredient in brewing was the last one discovered, because yeast is a single-celled organism that is invisible to the naked eye. Still, brewers have long known that some unseen agent turned a sweet liquid into beer. Modern brewers usually brew with purified strains of yeast that give exactly the result they want.