An isotope refers to elements with the same atomic number but different numbers of neutrons.

Rare earth elements are essential materials for the manufacture of electronic devices.

Hydrogen is the most abundant element in the universe.

Transition elements play an important role in chemical reactions.

He can speak many languages.

Protists are single-celled organisms that live in water.

All his prophecies came true.

I am majoring in linguistics at university.

This entrance is the gateway to a profound path.

The source of this river is at the top of the mountain.