Question

match each vocabulary term to its correct definition.
the breakdown of a radioactive element, releasing particles and energy.
the preserved remains or traces of an organism that has been preserved in rock.
a fossil used to date the rock - layer in which it is found.
the dying out, complete disappearance of a species.
radioactive decay
fossil
extinction
index fossil

Explanation:

1. "The preserved remains or traces of an organism that has been preserved in rock" - This is the definition of a Fossil. Fossils are the physical evidence of past - life forms that have been mineralized or otherwise preserved in the geological record.
2. "The breakdown of a radioactive element, releasing particles and energy" - This describes Radioactive Decay. Radioactive isotopes are unstable and transform into other elements by emitting radiation.
3. "The dying out, complete disappearance of a species" - This is the concept of Extinction. When the last individual of a species dies, the species is considered extinct.
4. "A fossil used to date the rock layer in which it is found" - This is an Index Fossil. Index fossils are fossils that are characteristic of a particular time period and can be used to determine the relative age of rock layers.

Answer:

1. Fossil
2. Radioactive Decay
3. Extinction
4. Index Fossil