What is a fossil? what is a fossil record?

A fossil is the remains of an animal that is not broken down, and generally is made up of bones.

A fossil record is the bones that are located within a certain part of the crust, and can tell us information on a certain time period, such as if there was a drought in a certain time period, a volcano eruption, etc. etc. based on the nutrients and other factors found in the soil.

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i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

youre right there are