Four actions which occur during inhalation in mammals

During inhalation in mammals, air from outside enters the lungs. The lung volume expands. The diaphragm constricts with expansion of the chest wall.

The "volume" of the "thoracic cavity increases" thereby leading to decrease in pressure relative to the environment.  

Breathing follows Boyle’s law which states that "pressure and volume" are "inversely related".  

A "slight negative pressure" is maintained in the lungs so as to keep the airways open. The drop in pressure due to "increase in volume of thoracic cavity" creates a pressure gradient. Air then rushes in from outside into the lungs.

the right side of the picture going down is:

polymerase

protein

transport vesicle

modified protein

the left side of the picture going down is:

dna helix

single-stranded rna

endoplasmic reticulum

ribosome

golgi apparatus

protein released from vesicle

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answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;