How does the mutation present in 10% of Europeans protect their cells from HIV?

The mutation, which affects a protein called CCR5 on the surface of white blood cells, prevents HIV from entering these cells and damaging the immune system. Around 10% of today's Europeans carry the mutation, a significantly higher proportion than in other populations.

Explanation:

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significant amounts of nitrogen oxides, carbon monoxide, and other pollution

explanation:

passenger vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. in 2013, transportation contributed more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air.