Radioactive elements are produced in nature and scientific experiments.

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

This radio is emitting music.

Sex chromosomes play a crucial role in determining the sex of an organism.

This area is affected by radioactive fallout from past nuclear tests.

An isotope refers to elements with the same atomic number but different numbers of neutrons.

This is my first question.

His body is very healthy.

He made three robots.

He exercises his body every day.