The people above must be so different. The people above must be tall! The people above, how don't they fall? The people above, can they see us? The people above, can they hear us? They mustn't be so different from us. Or are they as different as one can imagine. I really wonder about their sense of fashion. The people above, the rain must hit them first! The people above, is there water up there to quench their thirst? Is the air different? Do they speak differently? The people above, I wonder if I can see them if I climb up the tree! I really wonder if the people above are any different from you and me! Lets learn about the difference between us and them, let's try to figure out who they can really be!

When going into a higher altitude, people  have to adapt to the environment around them. The higher that you get in altitude, the harder the challenge becomes. 

As you get higher in the atmosphere, the challenge of climate, low humidity and air pressure must be faced and adapted to. The process of adaptation to these challenges at a high altitude is called acclimatization. 

People must adapt to the rapid change in climate. The weather at a high altitude can range from scorching hot days to freezing cold nights. It is usually more cold at higher altitudes because there is less air pressure. This means that the air molecules are spread further and less heat is absorbed. At a higher altitude the air loses more heat to space than it absorbs from the sun, directly resulting in the colder climates.

People also have to adapt to the loss of oxygen particles in the air as the altitude increases. This happens because the air pressure decreases, and the air becomes less dense and more thin (known as Boyle's law). The percentage of oxygen in the atmosphere is about the same from sea level to 3km up. After that threshold, the percentage of oxygen molecules in the air start to decrease, making it harder for people to breathe. This results in symptoms of "high altitude sickness" such as a lack of appetite, vomiting, headaches, distorted vision, fatigue, and difficulty with memorizing and thinking clearly. It also causes a strain to the lungs as they have to work harder to facilitate the osmosis between the oxygen and carbon dioxide, a strain to the heart as it must pump more red blood cells to carry oxygen, and a strain to the brain as it does not get as much oxygen as needed to function. If the lack of oxygen is not adapted to properly, major harm can be caused to the body, including death. Infact, if a person were to be taken from sea level to an extremely high altitude in a short amount of time, they would most likely die immediately due to these factors.

The things mentioned previously are things that happen to people who are travelling into a higher altitude. The people above live in these altitudes, so they in fact are already adapted to these changes. Their bodies have adapted to the colder climate and the lack of oxygen, and they live life normally as we sea level people do. Although, they have a better view from a higher altitude of course. The bodies of the people above have more red blood cells,  and a bigger lung expansion. This makes them have physical advantages compared to sea-level humans. In fact, many athletes train at higher altitudes to gain these natural physical advantages. This is a common thing for Olympic athlete's, as they train in the rocky mountains of Colorado. These physical characteristics would go back to normal if one were to stay at a sea-level atmosphere for some time, but they last long enough to give even the slightest advantage for these super athletes in the games. These advantages are also not felt at a higher altitude as it is an adaptation to feel normal at those heights.

The adaptation of the people above bodies can be elaborated on through Chemistry, specifically through equilibrium. As you've read, oxygen is a pivotal factor in the adaptation of a higher altitude. When the oxygen mixes with the bloodstream, it attaches to hemoglobin molecules, which are found in red blood cells. When the hemoglobin is exposed to oxygen, they together produce oxyhemoglobin, in a reversible reaction at equilibrium. 

O2 (g) + Hem (aq) <-> HemO2 (aq)

This is the chemical reaction at equilibrium which takes place in everyone's body at sea level. This reaction must be manipulated at a higher altitude for the people above.