How can scientists know the impact of prairie dogs on an ecosystem?

Smog is the term used to describe the combination of fog and smoke

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.

Transportation is the largest single source of air pollution in the united states. air pollution can harm the environment and human health. which technology could offer a solution to this problem? mufflers that reduce noise motors that run on electricity tires that improve gas mileage