What is the origin of this word?

He is majoring in linguistics.

The atomic number of helium is 2.

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.