Question about space, question in the photo.

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's c.us forest service

for a different answer set the answer would be because the oxygen in the water had depleted (apex)