Name a natural polymer

Example for a natural polymer can be "silk"

x would be the most and the least would be y because there are more fruit   and seeds than flock z has insects

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.