Passage Summary: In the lower atmosphere, it gets colder as you go up, reaching its coldest point at the boundary with the stratosphere. In the stratosphere, it actually gets warmer as you go higher because ozone absorbs sunlight.

Reasoning: In the troposphere, temperature decreases with altitude, reaching -50°C at the poles and -85°C at the equator. In the stratosphere, temperature increases with altitude due to ozone absorbing ultraviolet light.

Analysis: Since this is a 'Must be True' question, we need to synthesize the provided facts without adding outside information. We know the boundary where the stratosphere begins is significantly colder over the equator (-85°C) than over the poles (-50°C). Because the stratosphere starts at this boundary and warms up from there, the air at the very bottom of the stratosphere is colder above the equator than it is above the poles.