Liquid oxygen is often used as rocket fuel.

Please respond as soon as possible.

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.

Transition elements play an important role in chemical reactions.

Oxygen, which is one of the chemical elements, is necessary for us to breathe.

This area is affected by radioactive fallout from past nuclear tests.

Transitive verbs require an object that is directly moved by the subject.

He drank too much last night and became so intoxicated as to be out of control.

He suddenly stood up and left the room.