Can someone please help me with these? worth 50 points plus brainliest!!

Monitor and apply fix up stratorgies

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

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?