Radon is: select one: a. an alpha-emitting gas that penetrates the skin naturally. b. a naturally occurring gas produced during the radioactive decay of uranium. c. a metallic element produced in nuclear power plants. d. a secondary air pollutant resulting from photochemical smog. e. a by-product of nuclear energy production.

A

Explanation:

Radon is an alpha emitter. It emits alpha particles giving off gamma ray. It is a radioactive byproduct of radium-222.

Radon also penetrates the skin. This is because radon is a gas and chemically unreactive with most materials, it moves easily through very small spaces, such as those between particles of soil and rock, to the soil surface

Option B is wrong. It is produced during radioactive decay of radium and not uranium.

Option C is wrong. Radon is not a metallic element.

Option D is wrong also. It is not produced from photochemical smog

Option E is wrong. This is an extension of option B. Uranium is generally used in nuclear plant operations and not radium

what is the general relationship between a galaxy's distance from earth and its speed?

the answer is:

the farther away a galaxy is from us, the faster it is moving away from us.