Achange in the frequency of any mutant allele in a population most likely depends on the

The answer is ‘the degree of dominance of the selected allele with respect to fitness’. If natural selection favors the mutation, the allelic frequency will increase in the population. However, if the mutation is disadvantageous to the individuals with it, the allelic frequency will decrease and probably become lost.  

option c is the correct answer.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.