Each person makes more than 1 million different b cell antigen receptors and more than 10 million different t cell antigen receptors. how is such diversity in antigen receptors generated?

This is due to a phenomenon referred to as somatic hypermutation. The variable regions of the b and t cell receptors, including the variable region of the immunoglobulins, undergo rapid changes due to rapid mutations in the genetic material that codes them. This allows them to adapt quickly to novel invaders. This phenomenon is then followed by affinity maturation when the effective receptors and Igs are preserved

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.

it marks things for degradation via the proteasome. it alters there celluar location.