The Silurian period is one of the geological eras.

The Triassic period is one of the geological ages, referring to the period from about 252 million years ago to about 200 million years ago.

The Devonian period was a very important time in the history of the Earth.

The Quaternary is the most recent era in Earth's history.

At what point in Earth's history does the Triassic period fall?

The Triassic period is one of the geological ages, referring to the period from about 252 million years ago to about 251 million years ago.

I use a set square to draw shapes.

In chemistry class, I learned about acid anhydride.

In chemistry class, I learned about acidic oxides.

Lower fatty acids play an important role in the human body.