Many athletes use altitude training to improve their performance. They travel to areas of high altitude where there is less oxygen in the air. The body adapts to the stress of less oxygen by becoming more efficient at transporting and using oxygen. What are athletes who train in high altitudes most likely trying to enhance?

Its A

Explanation:

Energy Production in the Mitochondria because of the lack of less oxygen you would want to build up more ways to get more energy production going

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods