True aka pollution from machines smoke carbon emissions etc
        
                    
             
        
        
        
The correct answer is "limited prey is driving the bears to seek food in human settlements".
Due to the warming of the Arctic waters, the ice is melting, resulting in a serious decline of floating winter ice. Polar bears need these floating parts of ice to hunt, therefore this new situation limits the hunting opportunities of the bears. That is why polar bears are driven to human settlements to look for food.  
        
             
        
        
        
Answer:
I think that birds have different bill lengths because of their habitats and their diet. Also natural selection and evolution has also played a factor due to the fact that birds have not always looked the way that they do now, for example the Archaeopteryx a  bird that lived around the time of the dinosaurs had a shorter and more powerful bill to grind insects and small mammals
Explanation:
 
        
             
        
        
        
Answer:
Krill
Explanation:
All animals in the Antarctic depend on krill, very small crustaceans, for their survival.