Organelles are specialized structures that perform important cellular functions; they are structures you can generally see only under a microscrope. which of the organelles below would you expect to find in all living cells?

1. cell membrane

2. DNA

3. cytoplasm

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.