Question

Oxygen is composed of only one kind of atom and can’t be separated into simpler substances. What type of matter is it?

solution

element

mixture

compound

colloid

Answer 1

Definetely element.

Hope this helps!

Answer 2

Element

Step-by-step explanation:

When atoms can't be chemically separated into simpler substances, they are an element.

Alternatively: Oxygen can be found in the Periodic Table of Elements. Thus, it is an element.

All the other options (solution, mixture, compound and colloid) refer to different way in which two or more substances (be it elements or molecules) are together.