Which principle states that fossils will be placed in rock layers according to a chronological order?" -faunal succession
-perimineralization
-index fossilization
-carbonization

Faunal succession states that fossils in rock are placed in rock layers according to a chronological order

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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.