D is the answer because the rest ate observations
Good define unemployment as having no job teheheheh
Ammonia synthesis exponentially increased harvests and will continue to do so for years to come. His invention is credited with saving millions of lives and will probably save billions more.
Photosynthesis is used by plants for energy. In addition to carbon dioxide and water, light and chlorophyll are required for photosynthesis to work.
The answer is D. Just think how hard it would be to see a moth of that colour when just about everything during that time period is grey.
