Identify the statement which is correct about radioactivity.

Radioactive elements are dangerous because cells within the body preferentially incorporate radioactive atoms in their structures.

Since radioactive elements have unstable nuclei, they all form cations due to the loss of electrons.

Only those radioactive elements are dangerous which are artificial, naturally radioactive ones are safe.

Energy released by radioactivity can break chemical bonds and therefore damage the delicate structure of cells within the body.