<span>C. a severe degrading of watersheds which leads to increased soil erosion and a decrease in the
quality of drinking water</span>
Answer:respiratory system
Explanation:The primary function of the respiratory system is to deliver oxygen to the cells of the body's tissues and remove carbon dioxide, a cell waste product. The main structures of the human respiratory system are the nasal cavity, the trachea, and lungs
This is only one part of the answer, but its important: high-altitude O2 absorbs much energy from the sun (including radioactivity), which forms the ozone layer. this process protects delicate molecules important to life - most notably dna
