Question

1. Which of the following is NOT a mixture? A. Oxygen B. Soil C. Ketchup (catsup) D. A rock​

Answer 1

Oxygen is the correct answer. Oxygen is a molecule not a mixture though it is made from two atoms that are the same type.

Answer 2

A. oxygen

Step-by-step explanation:

because that oxygen is made up of only one element (that element is Oxygen) it rules out oxygen being a mixture unless you add something like nitrogen but then it would not be oxygen anymore