In geography, a tropic indicates a specific latitude on the earth.

In meteorology, an isotherm refers to a line on a map that indicates the same temperature.

Please turn on the power after checking the ground wire.

In this map, the longitude lines are clearly displayed.

These two lines are on the same extension.

A good antenna is needed to improve the reception quality of this TV.

Please change the borders of this box to red.

This electrical appliance is made of copper wire.

He observed the stars using the reticle of the telescope.

The study of sound waves is an important part of acoustics.