Final answer:
The troposphere contains a higher concentration of oxygen than the stratosphere because it holds around 80% of the atmosphere's total mass and the air composition is around 21.0% oxygen.
Step-by-step explanation:
The question asks which layer has more volume of oxygen, the troposphere or stratosphere. The greatest concentration of oxygen is located in the troposphere, which is the layer closest to the Earth where most of our weather events occur. This is because approximately 80% of the total mass of the atmosphere is here, and the composition of air is around 21.0% oxygen. The stratosphere, on the other hand, sits just above the troposphere and extends up to 50 km above the Earth. Within this layer, ozone (O3), a type of oxygen molecule, is found. The ozone absorbs the majority of the Sun's harmful ultraviolet radiation, which is crucial for life on Earth, but the overall concentration of oxygen in the stratosphere is lower than that in the troposphere.
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