Which model correctly explains the meaning of 3’ and 5’ in nucleic acids?.

 5' carbon is bonded to the phosphate group and the 3' carbon is bonded to an OH group.

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.

whats the answer to your question?