There's been a lot of bad news for polar bears recently. In 2007, for example, scientists reported that if global warming continues unabated, the population could drop two-thirds by 2050.
The correct answer is (d.) proteins. Higher organisms use nitrogen to make their protein. Food that is containing protein also involves nitrogen in it. Protein also has amino acids that contain nitrogen in it which is a necessary essential nutrient for the body.
B. The area's climate
Specific plants need specific climate conditions in order to survive. The other answer choices have little to no impact on the growth of plants.
The muscle elevates and/or adducts a region.
