Altitude is the height of a given point above sea level.
<u>EXPLANATION:</u>
The altitude is the height of a specific area measures relative to the sea level. As the "altitude increases", the temperature decreases and oxygen molecules decrease.
This is one of the main reasons why many people get sick when they reach higher altitudes.
It is also not very easy to "adapt to high altitudes" because of the weather and other environmental conditions.
