Answer:
B. Design homes that can be built on stilts where flooding is likely to occur.
C. Replace power lines that have been damaged by severe weather.
Explanation:

I believe it would be a compound.
In plants, these energy factories are called chloroplasts. They collect energy from the sun and use carbon dioxide and water in the process called photosynthesis to produce sugars. Animals can make use of the sugars provided by the plants in their own cellular energy factories, the mitochondria.
Oxygen - element
Water - compound
Ocean - liquid solutions
Air - gaseous solution
Cloud - colloid
Composting is not a technological way of improving air quality.
I hope this helps!