Suppose you found a fossil of a clamshell. what can you conclude about the once-living organism and how it became a fossil?

Identifying the fossil is the first step. We have already identified this fossil as a clamshell. We know clam are from the sea, but if you didn't, you could conclude this from knowing where you found the fossil (likely near the beach). Discovering where it is can also lead you to a conclusion on it's arrival as a fossil, perhaps washed up on shore or buried by an animal.