Alex listed the typical steps of fossil formation.1) An organism dies.2) The remains fall to the bottom of the ocean.3) The soft portions decay, and the hard portions remain.4) The sediment becomes rock.

After the organism dies and its remains settle on the ocean floor, the soft parts decay while the hard parts remain. Next, layers of sediment cover the remains, and over time the sediment hardens into rock. So the missing step belongs after step 3: “layers of sediment cover the dead organism.”

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