This document discusses natural resources and their value. It defines natural resources as materials found naturally on Earth that satisfy human needs and add value, such as rocks, soil, rivers, plants and animals. Natural resources are categorized as biotic resources (living things like forests and animals), abiotic resources (non-living things like air and water), and renewable resources that can be replenished easily, like sunlight. The document notes that natural resources have economic value through production, legal value in maintaining clean air and water, and aesthetic value in natural beauty.