Clearing land is not a sustainable practice in any form, so not A. Crop rotation is important for maintaining soil fertility, but is not necessarily sustainable. It's definitely not C. It is likely D because using only renewable resources is top notch sustainability.
The Earth's atmosphere would have little or no oxygen. A by-product of photosynthesis is oxygen. Photosynthesis is the process by which green plants use energy from the sun to make their own food in the leaves. The process uses sun light, water and carbon dioxide to yield oxygen and simple sugars. The simple sugars are stored in form of starch for future use by the plants, while oxygen is either used for cellular respiration or released to the atmosphere. The process of photosynthesis adds oxygen to the atmosphere and uses carbon dioxide from the atmosphere.
Hybrid cars, efficient transportation, and fuel cells
If this occurred the cells won't have the same DNA
The Corona is made up of plasma surrounding the sun. The Corona I saw Latin for crown, and the Corona is basically a crown of plasma around the Sun and other stars.