One source of background radiation is ______________.

Hint:Background radiations are those that come from a radioactive compound in the earth's crust as well as particles and rays entering the atmosphere.Background radiation comes from a number of natural and man-made sources.

Complete answer:
Background radiation comes from a number of natural and man-made sources. Cosmic radiation and ambient radioactivity from naturally occurring radioactive elements (such as radon and radium), as well as man-made medical X-rays, fallout from nuclear weapons tests, and nuclear accidents, are all examples.

One of the sources of background radiation is rock and soil. Background radiation comes from a variety of natural sources.
-Cosmic rays – radiation from space that enters Earth.
-Rocks and soil – some rocks are radioactive and emit radioactive radon gas
-Living things – plants absorb radioactive materials from the soil and move them through the food chain and food web.
-Natural sources account for the majority of people's background radiation dose.

Additional Information:
Airborne radon, a radioactive gas emitted from the atmosphere, is the most significant source of natural background radiation. Since radon is unevenly dispersed and varies with weather, much higher doses are needed in many parts of the world, where it poses a serious health risk.

Note:Artificial exposure is, on average, greater than natural exposure in some developed countries, such as the United States and Japan, due to greater access to medical imaging. Since there is no large amount currently delivered to the Earth, most terrestrial sources have been declining due to radioactive decay since the Earth's formation.