How does scientific knowledge continue to change over time

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.

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.