Carrots and potatoes are parts of the root of the plants, but since they are eaten by humans, they are vegetables. They are not in the same category as a fruit, nut, herb, spice, or grain. Though tomatoes are often thought of as vegetables, but because they have seeds, they are, botanically, fruits. Vegetables are an important part of people's diet. Vegetables and fruits are sometimes called produce. Vegetables have vitamins A, B, C, D, minerals and carbohydrates.