Final answer:
Nitrox is a homogeneous mixture, or solution, consisting of oxygen and nitrogen used to fill scuba tanks.
Step-by-step explanation:
Nitrox, which is a combination of oxygen and nitrogen used to fill scuba tanks, is a mixture rather than a pure substance. It is specifically a homogeneous mixture, also known as a solution. In this case, the mixture is uniform, meaning that the oxygen and nitrogen are evenly distributed throughout the scuba tank.