What do you think about G protein vs β-arrestin signaling bias at GPCRs?

b. the carbon cycle ensures living things have a source of hydrogen

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.