Short answers, pulled from the story.
Mount Everest, in the Himalayas of Asia, is the highest mountain on Earth, with its summit 8850 m above mean sea level. At least 100 mountains rise over 7200 m above sea level, all located in central and southern Asia.
Mauna Kea in Hawaii is the tallest mountain on Earth measured from base to peak, rising 9,330 m from its base at the bottom of the ocean. Some scientists consider it the tallest on Earth for this reason.
Mountains are formed through tectonic forces, erosion, or volcanism, acting over time scales of up to tens of millions of years. The three main types are volcanic, fold, and block mountains, all produced by plate tectonics.
The death zone refers to elevations above 8000 m, where there is not enough oxygen to support human life. The summits of Mount Everest and K2 both lie within it.
Mountains cover 24% of the Earth's land mass under the UN Environmental Programme's definition. By region they cover 33% of Eurasia, 24% of North America, 19% of South America, and 14% of Africa.
Climate on mountains turns colder at high elevations because of an interaction between radiation and convection. As air rises and pressure drops, its temperature falls at the adiabatic lapse rate, about 9.8 °C per kilometre when dry and about 5.5 °C per kilometre when moist.
La Rinconada, Peru, a gold-mining town at 5100 m, is the highest human habitation in the world. The highest known permanently tolerable altitude is 5950 m.