UVC rays are mainly absorbed by this layer of the atmosphere:

UVC rays are primarily absorbed by the ozone layer, which is located within the stratosphere. The ozone layer contains a high concentration of ozone (O3) molecules that effectively absorb the majority of the sun's harmful ultraviolet radiation, particularly the UVC rays. These rays are the most energetic and potentially damaging to living organisms, capable of causing skin cancer and other health issues.

While the stratosphere is the atmospheric layer that includes the ozone layer, it is specifically the ozone itself within this layer that plays the crucial role in absorbing UVC radiation. The other layers mentioned do not have the same protective capability against UVC rays. For example, the troposphere contains weather and life but lacks significant ozone concentration to filter UVC rays. The exosphere is extremely thin and is not involved in absorbing UV radiation, while the term "ozone layer" explicitly refers to the specific region within the stratosphere responsible for this protective effect.