Hey there!
Airplanes must be pressurized when flying at high altitudes so that the oxygen levels stay normal for us to breathe. The higher you go up, the thinner the air gets, which causes breathing problems for us humans.
Thank you!
Answer:
Water
Explanation:
Water is essential to human life. Hence, human settlements tend to crop up near water sources such as rivers. This is particularly evidence in Africa, which has many quite dry regions.
Answer: 
Explanation:
We are asked to multiply 1 nano sec with 1 km/sec.
The conversion used from nano second to second
1 nsec = 
The conversion used from km to meters:
1 km = 1000 m
Putting the values we get:
Therefore, the given conversion is
The continental plate is less dense that the oceanic plate and so sinks underneath the oceanic plate. The oceanic plate holds water and so when the continental plate sinks underneath it, the water from the oceanic plate covers the continental plate.
If it is humid and/or hot out, the wet bulb (since it is wet) evaporates water, causing the gauge to go up. I'm not sure about dry bulb though.
