Alguien sabe cómo hacer esto?

What does x represent in the formula for the compound xcl4?

This drawing shows a human body system. what is the primary function of this body system?

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.