Radioactive elements are produced in nature and scientific experiments.

This rock is radioactive, so care must be taken when handling it.

Americium is one of the radioactive elements.

He ate one apple.

Education about sex is very important.

Hydrogen is the most abundant element in the universe.

Sufficient caution is necessary when handling radioactive materials.

This radio is emitting music.

This area is off-limits due to high radiation levels.

This area is seriously contaminated with radioactive isotopes.