The diaphragm,
During inhalation, the diaphragm is contracted which increases the volume of the lung cavity. During exhalation, the diaphragm is relaxed which decreases the volume of the lung cavity
As in printing a book, if there is a slight defect in the mutation, it will be copied to every other mutation, just like a grammatical error in a book.
C. nucleus is the part of the atom that has most of its mass
