Atmospheric layers (ionosphere): The ionosphere contains ionised air which helps protect the Earth—mainly from which solar radiation? Consider which band is significantly absorbed by high-altitude ionised layers rather than by lower atmospheric layers. Choose the most appropriate option.

Given data

• Ionosphere = ionised region at high altitude.

Concept/ApproachThe ionosphere absorbs a significant portion of solar extreme ultraviolet (EUV) and X-ray radiation, protecting the lower atmosphere. (By contrast, most incoming meteoroids ablate primarily in the mesosphere; IR is not chiefly attenuated by the ionosphere.)

Final AnswerThe ultraviolet rays of the Sun