Based on the clue 'at over 200 people per square mile it has the high...', what is the answer?

Based on the clue 'at over 13 million acres its the largest subtropic...', what is the answer? What is associated with: at over 15000 feet high the highest railway station in south america is in condor in this smal… Based on the clue 'at over 155 miles high the martian mountain known ...', what is the answer? What is associated with: at over 17000 feet mount kenya is eclipsed by only this other peak as the highest in africa? Based on the clue 'at over 30 years this west virginian is currently ...', what is the answer? Based on the clue 'at over 330 pounds you might say this wilson prede...', what is the answer? What is associated with: at over 3500000 square miles this desert covers an area larger than australia? What is associated with: at over 36000 feet its the deepest spot in the north pacific or anywhere else on earth?