Einstein proposed the theory of relativity.

His actions always have a duality.

Radioactive elements are produced in nature and scientific experiments.

This software has forward compatibility.

This software maintains backward compatibility.

He was diagnosed with congestive heart failure.

His father fell into a persistent vegetative state due to a traffic accident.

It is important for us to respect cultural diversity and understand each other's differences.

She was diagnosed with polycystic ovary syndrome.

This area is seriously contaminated with radioactive isotopes.