Four elements that comprise over 95% of the human body are .

oxygen, carbon, hydrogen, and nitrogen

Explanation:

These four elements—oxygen, carbon, hydrogen, and nitrogen—together make up more than 95 percent of the mass of the human body, and the body cannot make elements, so it is helpful to have them in consumables.

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint