This question text is too difficult, it's hard to understand.

The Solar System is composed of eight planets, including Earth.

In this experiment, we will use the International System of Units.

We use this coordinate system to locate the position of an object.

We are a part of the Milky Way.

He found her on a dating website.

In physics, the inertial frame of reference is a very important concept.

This system is very complex.

He is deeply involved in the study of the meridian system.

Because her immune system is weak, she catches a cold easily.