The pineal body is a small endocrine gland located in the brain.

I have experienced astral projection.

He said he had experienced an out-of-body experience.

Chloroplasts are the locations where photosynthesis occurs in plant cells.

In our medical class, we learned about the function of the pyramidal tract.

A tesseract is a four-dimensional geometric shape.

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

This area is seriously contaminated with radioactive isotopes.

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

The study of filterable pathogens is an important part of virology.