A sea lion is a type of marine animal, and it is very rare.

The sea otter is a rare animal, and its ecology is not well known.

The sea otter is a very rare animal.

The Arctic Ocean is a cold and beautiful sea.

The South Polar Ocean is the coldest sea on Earth.

I have visited the Ionian Sea.

The Bohai Sea is one of the important sea areas of China.

I would like to visit the Dead Sea someday.

Sea turtles play an important role in the marine ecosystem.

This sea urchin is fresh and delicious.