22. During which stage of embryonic development do organisms begin developing distinct characteristics? ​

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the 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.

the answer is sex-linked recessive.