I would select B or C as the answer because i have no idea what the other ones are :)
Answer:
The forests
Explanation:
Forests are so much more than a collection of trees. Forests are home to 80% of the world's terrestrial biodiversity. These ecosystems are complex webs of organisms that include plants, animals, fungi and bacteria. Forests take many forms, depending on their latitude, local soil, rainfall and prevailing temperatures.
Well theory isnt proven. It means you have a strong idea about the subject your talking about. So if a scientist finds evidence that suggests something against the theory then it can be changed.
Cancer is a mutation of multiple cells through the cell cycle. cancer doesn’t only effect one cell, but effects many