The correct answer is C.
The hiking boots and the sleeping bag are two products that she bought and which are necessary for the hiking trip. On the other hand, the want is the pair of jeans, which is a product that she desired and bought, but that is not necessary or useful for the coming trip.
Answer:
is this a book ? please give more information! thank you
Breathing begins with inhalation when the contraction of the diaphragm flattens on contraction, pulling the lungs down. The contraction of these muscles increases the volume of the lungs. This reduces the air pressure in the lung to below that of the external air. This pressure difference forces air to move into the lungs where gas exchange occurs. The relaxation of the diaphragm and intercostals reduces the volume of the lungs, which then increases the air pressure inside the lung to that above the external air. This forces air out of the lungs. The cycle goes on and on. Hope this helped!