Answer= Because polar bears depend on ice as a habitat to survive the more the temperature is rising and the sea ice melting as a result of global warming there is basically a possibility that the population of polar bears will decline because there will be no home (habitat)left for them to breed(survive)in.
        
                    
             
        
        
        
Answer:
Why do marathon runners collapse and die? Some of the reasons why marathon runners often collapse near the finishing line is because the build-up of lactic acid in the blood during the run triggers abnormal heart rhythms and also exhaustion, emotional stress, dehydration and heat stroke
 
        
                    
             
        
        
        
The sun with out it nothing would exist it would just be a cold solid rock floating through space.
        
             
        
        
        
Answer:
The correct answer will be option- Insulin.
Explanation:
Gluconeogenesis is the process of formation of sugar glucose from the non-carbohydrate sources during the less or no intake of carbohydrate from the diet.
Gluconeogenesis is controlled by a feedback mechanism which could be positive or negative. The positive feedback is controlled by the hormones like  epinephrine, cortisol and glucagon but insulin shows negative feedback mechanism and inhibit the process.
Thus, option- Insulin is the correct answer.