Answer:
A. Earth's gravity pulling down on air molecules
Explanation:
Air pressure refers to the weight of the air per unit surface area. It is the amount of gravitational force which is pulling down the molecules of air.
The common unit of air pressure is: Pascal, atm
1 atm = 101325 Pa
As the column of the air above increases, the air pressure increase. This is because with the increase in amount of air, the weight increase of the air increases. This is the reason a diver feels immense pressure in the sea and cooking takes a lot of time on hilly areas because of low air pressure.
The answers to the respiratory questions are listed below:
- 6). Trachea
- 7). Pneumonia
- 8). True
- 9). False
- 10). Hair
<h3>Meaning of a respiratory system</h3>
A respiratory system is a biological system found in both plants and animals, which includes organs and structures used for exchanging gas between the organisms and its environments.
A respiratory system is a network or chain or organs and tissues that enables breathing.
In conclusion, the respiratory system is one that is very important to understand.
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Answer:
Say the full question I can't understand what it is
For the part a) we need only the momentum of the box and we have the data to find it.
Momentum is given by,

where clearly, p is the momentum, m the mass of the box and v is the velocity.
Substituting,

For part b) we need an analysis of the situation. We understand that the box on a surface that has no friction will continue to rotate at the same speed previously defined. The box can only stop with friction, so,

<em>It is the same that part a)</em>
The correct answer is option #4. The greatest obstacle to developing solar energy is large areas required to collect sufficient energy. Solar energy is the energy that is the sun is producing and being converted into thermal energy that can be used for everyone's daily lives.