Im not writing your essay but some plants are used as medication and other remedies. plants are important because they provide food, medicine, oxygen, etc.
Answer:
it increases oxygen levels and decrease carbon dioxide levels
Answer:
Due to its spreading nature.
Explanation:
Transboundary environmental threats like pollution is a problem for both parties i. e. one that is producing pollution and the other which is not producing it, because pollution can't remain at one place and spread from one part to another part of the earth due to open environment. So due to its spreading, it affected both the producing and non-producing parties.
The answer is B I'm pretty sure of it.
Here is what I found, its quite interesting, I hope it helps..
https://www.fbi.gov/services/laboratory/biometric-analysis/codis/codis-and-ndis-fact-sheet