Carrots belong to the parsley family and are an excellent source of vitamin A, which actually accumulates during the months of storage after the carrots have been harvested. Carrots have few rivals when it comes to beta-carotene. Just a half-cup serving of cooked carrots provides four times the RDA of vitamin A in the form of protective beta-carotene. Their sweetness intensifies, too, during storage. Only beets have a higher sugar content among root vegetables. Look for smooth, firm, brightly colored carrots without cracks or any green, whitening or sprouting around the stems. Slender, mature carrots are the tastiest. The greens draw moisture and nutrients from the orange carrot roots and should be removed and discarded as soon as you get the carrots home.