As an airplane rises through the atmosphere, machines cause the pressure inside the cabin to decrease. as the airplane descends toward earth, machines cause the pressure inside the cabin to increase. based on your observations from the can crush lab, explain why these changes in pressure are necessary.

In higher elevation, there is the presence of lesser molecules of air above a given surface in comparison to the similar surface at the lower levels. The majority of the molecules or atmosphere are held close to the surface of the Earth due to the gravitational forces, and thus, air pressure declines briskly at the initial stage, and then more gradually at the higher levels.  

Thus, if the pressure in an airplane cabin does not change, then it can even result in harm or injury to the passengers and there will be a requirement of oxygen equipment at the height of 8000 meters.  

children tend to take more after their grandparents more than their parents. it’s the dna you received that was passed down to you somewhere in your family. maybe one of your grandparents had/has straight hair and you might have gotten it from them.

it takes hundreds of years to become stable.

if you have another question lmk.