1. A mixture of red and green lights is perceived as yellow.
2. Cryptochrome is a pigment that absorbs blue light. Therefore, it transmits red and green light. These would be perceived as yellow.
3. Lowest: far-red light inhibits germination. Middle: the absorption spectrum for phytochrome will slightly overlap pure yellow. Highest: yellow light obtained by mixing red and green light. The red light component stimulates germination.