round 3

A vacuum is a space filled with no air.

A proton carries a negative charge

Metals are poor conductors of electricity

The periodic table arranges elements randomly

Vertebrates are animals that do not have a backbone

Compounds are made by mixing different substances physically.

A parallel circuit has only one path for electricity to flow.

If a scale shows different weights each time the same object is measured, it is highly precise.

Alloys are always weaker than pure metals.

In a dichotomous key, each step provides three or more choices