There are natural, chemical, biological, radiological, and behavioral hazards that pose risks to humans. The potential for accidents and the existence of hazards impose the need for injury prevention. These grade level performance standards are listed developmentally. However, each school is uniquely organized. Natural environments contain substances harmful to living organisms.
Some activities practiced by humans can accelerate natural changes.
Scientists formulate and test their explanations using observation, experiments, and theoretical and mathematical models. People, cultures, and events in history have and will continue to advance science and technology. These grade level performance standards are listed developmentally. However, each school is uniquely organized. Risk analysis considers the type of hazard and estimates the number of people that may be exposed and the number likely to suffer consequences.