This bacterium is about 1 micrometre in size.

There is a New Year's celebration in January.

He always likes to be the first to comment on videos.

The tip of this pen is only 1 millimeter.

This room is 20 square meters.

The beluga whale lives in the Arctic Ocean.

The harbour porpoise is a small dolphin that lives in the cold sea areas of the Northern Hemisphere.

Delphinus is one of the most beautiful constellations in the night sky.

The Amazon River dolphin is known for its distinctive pink color.

The river dolphin is a rare type of dolphin that lives in freshwater.