19 crossing over is one of the most important events in meiosis because

The crossing over process is considered to be the most important event when it comes to the process of meiosis because the crossing over in the meiosis enables them to produce new arrays of alleles in which is found in the chromosomes.

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.