A、Living things. B、Living things and nonliving things. C、The environmental problems caused by industry and people. D、The interre

Ecology is the study of the interrelationship of living things to their environment. This even includes the study of nonliving things. In recent years, ecology has become a source of great interest to many people who live in the United States and Canada. The interest has been increasing because some experts feel that we are destroying the land on which we live. They also feel that we can stop this destruction by being more careful.
    Some of the environmental problems are caused by industry. Wastes pollute the waters. Gases and fumes poison the air. When air and water are polluted, then fish, birds, and other living cream die. Human life is also affected by industrial neglect. People become poisoned in many ways while working on and around unsafe plants and factories. Nuclear power plants have caused great controversy.
    People also cause some of the problems. Cars that people drive pour fumes into the air we breathe. Garbage is sometimes dumped into streams that supply drinking water. Forest fires are often caused by careless campers. Beaches and city streets are littered with rubbish.