I booked a business class for the next flight.

I will take a flight in economy class.

This culture liquid contains various types of bacteria.

Archaebacteria are one of the oldest life forms on Earth.

He is a world-renowned bacteriologist.

He specializes in the study of fish claspers.

Long-haul flights increase the risk of economy class syndrome.

You must be careful of economy class syndrome on long flights.

He has a deep interest in archaeology.

My personal thought is that everyone should be treated equally.