I think that the answer is B, because I had this question a while back in Junior High.
Answer:
1. the answer is b; the passage is mostly about living walls and how they help
2. the answer is d; the sentence before talks about 'high rise buildings'
3. the answer is a; air conditioners are an example of energy use
4. the answer is d; the first three words are 'containers holding soil'
5. the answer is d;
6. the answer is d;
i'm not sure on all of these so you may want to check my answers before using them(if you do decide to)
I'm fairly certain it's the first answer but it may be the third answer as well but I believe it's the first more though.