He is undergoing training for extravehicular activity.

He engaged in an extravehicular activity from the spaceship.

We crossed the sea by catamaran.

The shipworm is known for eating wood.

Mr. Hiruma is my best friend.

Well, let's get started!

The mesentery plays a role in supporting the intestines.

Interracial marriage promotes diversity and understanding.

Intermolecular forces are an important factor in determining the properties of a substance.

His work progress is slow.