The correct answer is option 3: dead and decaying material. Saprophytes are organisms that obtain their nutrition by feeding on dead and decaying matter. They play a vital role in the ecosystem as they help in the decomposition process. Option 1, living plants, is incorrect because saprophytes do not feed on living plants. Option 2, living animals, is also incorrect as saprophytes do not rely on living animals for food. Option 4, inorganic chemical compounds, is not accurate because saprophytes derive their nutrition from organic matter, not inorganic compounds. It is important to note that while saprophytes obtain their food from dead material, they are not the same as decomposers. Decomposers break down and recycle organic matter, whereas saprophytes specifically rely on dead and decaying material as a food source.