Explain various types of fossils?

Mold fossilsA fossilized impression made in the substrate; a negative image of the organism.

Cast fossilsFormed when a mold is filled in.

Trace fossils or IchnofossilsFossilized nests, gastroliths, burrows, footprints, etc.

True form fossilsFossils of the actual animal or animal part.

doctors i believe if i'm wrong sorry

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.