Plankton are microscopic organisms living in large bodies of water. They are a major food source for several kinds of sea creatures, and although they are tiny, they have a major impact on many other living things. Accessible explanations of marine life, food chains, and other essential science curriculum topics enhance readers' knowledge of the natural world and the part every living thing plays in it. Additional features, such as fact boxes and full-color photographs deepen readers' understanding of these tiny yet hugely important creatures.