There numerous of them but some of them would be contaminated soil which can be followed with altered soil chemistry that contains fewer soil organisms that are essential. The third one would be surface runoff due to extensively modified hydrology of the area.
As you grow older, you would need to remain physically active to keep a good level of physical fitness.
Answer: T
I am more of a chemistry person, but my best answer is the double-helix structure. The DNA rotate around a central point allowing it to keep a constant distance
The tree would contain carbon.