Which of the following choices is not considered an environmental stressor?
a. flashing lights
b. heavy traffic
c. cancer
d. loud noises

C. cancer

Upward urban growth will increase pollution as the number of people will increase. The increase in population and obstruction of free movement of air because of upward urban growth will result in a "heat island". Since the number of inhabitants is going to increase with upward urban growth, waste management will also become an issue.Human economics and ecology are linked together because human economics utilizes the ecosystem and the natural resources in order for economics to actually exist. As living organisms in the biotic environment, human beings need food, water and resources in order to survive and thus, it is used in trading, buying and selling of the goods, where economics function. It also applies the supply and demand approach and uses strategy in how to maintain and innovate resources.   

The one that most represents the earths mantle would be the skin since the mantle is the upper part of the earths depths which is just like the skin of an apple.