His role is to fulfill his responsibilities as a leader.

It is important to understand the importance of health.

The Commonwealth of Independent States is an intergovernmental organization formed by part of the former Soviet Union.

This area is seriously contaminated with radioactive isotopes.

In Christianity, God is considered as the Trinity of the Father, the Son, and the Holy Spirit.

In organic chemistry, the concept of cis-trans isomers is important.

In organic chemistry, the concept of conformational isomers is very important.

A tesseract is a four-dimensional geometric shape.

A 5-cell is a simple convex polytope in four dimensions.

He is an expert in immunology.