Answer:
Ozone layer... pollution
Explanation:
The ozone layer is a layer in the atmosphere which provides a barrier between harmful UV rays and the Earth. However, pollution is quickly depleting the layer which in turn creates a higher risk of skin cancers and other conditions caused by harmful UV rays.
B.
Viruses are classified as biological agents instead of a living things, $& they are only made of genetic material.
they could possibly learn the climate the animal was from or even relative dating & absolute age
