They use a internal pouch which is named swim bladder.
Explanation; Oxygen will enter a fish’s mouth, and passes through their gills. The oxygen will be taken and gets carried by hemoglobin through their bloodstream. Hemoglobin will take out some of the oxygen into their swim bladder. The amount of oxygen will show if they will sink or rise. Your question is how do they rise. If he goes up too much, the meaning of this is when the gas diffuses into their blood and out the gills.
Got this from a writing, but rephrased it.
Answer:
c they let people know what dinosaurs looked like
Smooth muscle, also called involuntary muscle, muscle that shows no cross stripes under microscopic magnification. It consists of narrow spindle-shaped cells with a single, centrally located nucleus. Smooth muscle tissue, unlike striated muscle, contracts slowly and automatically.
