This new software maintains upward compatibility with the old version.

The prevention of venereal diseases is most important in safe sexual behavior.

This equation has homogeneity.

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.