Umi is my best friend.

He found the sea on an old map.

He found the sea on an old map.

I love swimming at the seashore.

I often go to the sea on weekends.

Protecting the biosphere is important for the future of the Earth.

In marine biology, plankton is an important part of the marine ecosystem.

Protists are single-celled organisms that live in water.

Microorganisms are one of the basic forms of life.

Biotechnology plays a very important role in the medical field.