Which one of the following pollutants is responsible for the increase in skin cancer?

During the winter, this species of fox has white fur, but in the summer, it has brown fur. what environmental change may have lead to this fox's fur color? snow cover increase in sun's brightness volcanic eruption global warming

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks

In which part of the body is a ball-and-socket joint found?