Color is the attraction. Rainbow, autumn, foliage and flowers is one example. How does the one noun (e.g. leaves) has a green color while the other objects have color orange (carrots for example)? If seen from its chemical structure, leaves are green because of chlorophyll and carrot orange because it has a beta carotene. If seen from the structure of the molecule, chlorophyll and beta carotene have a molecular structure as shown in Figure 1.