How flowers and other plants continue to reproduce is clearly explained and illustrated on the opening spreads. The most common pollinators are bees, wasps, butterflies and other animals that visit flowers. There are three types of pollination—cross-pollination, self-pollination and wind pollination. These words are bolded and they are clearly explained in the text so they are not repeated in the glossary. If you have wondered why some people have an allergic reaction to ragweed it is due to wind pollination.