Walt listed the steps that occur during the formation of natural gas. Plants and animals that live in a lake die. The dead plants and animals sink to the bottom of the lake. Sand, dirt, and rocks bury the plants and animals. The dead plants and animals are exposed to extreme heat and pressure. Within about twenty years, natural gas forms. Which best describes Walt’s mistake? Only dead plants form natural gas. Land plants and animals form natural gas. Natural gas only requires extreme pressure to form. Natural gas takes millions of years to form.