Botanists use water during their studies often. Botany is the scientific study of plants. Some of these plants include flowering plants, mosses, and fungi. All plants need water in order to survive. They need water in order to grow. Water normally takes up 80 – 95% of the mass of a growing plant's tissue. They also can study the affects of pollution such as acid rain on the plants. They also study the effects of pollution on the water and on the environment. Botanists water plants and they then measure the plants. They may specialize in limnology, which is the study of freshwater plants. Limnologists also study inland waters, such as lakes, resiviours. and rivers. They can study plants that float in water such as duckweed.