Answer: A rise in temperatures has disrupted the Arctic food chain common to polar bears.
Step-by-step explanation:
Global warming is the sustained increase in the average temperature of the earth, sufficient to cause climate change.
This rise in temperature has denied polar bear the presence of ice caps, that they usually get on in their hunts for seals. Consequently, the Arctic FOOD CHAIN has been disrupted, as polar bears are less likely to feed on seals
Note that other options DO NOT give the impact of global warming on polar bears