____ 20. relative dating a species that has no living members ____ 21. half-life the preserved remains or traces of an organism that lived in the past ____ 22. radioactive dating a way to determine the actual age of fossils ____ 23. extinct rock made of hardened sediment ____ 24. sedimentary rock the time it takes for half of a radioactive ____ 25. fossil sample to decay a way to determine which of two fossils is older
____ 20. relative dating ____ 21. half-life ____ 22. radioactive dating ____ 23. extinct ____ 24. sedimentary rock ____ 25. fossil a species that has no living members the preserved remains or traces of an organism that lived in the past a way to determine the actual age of fossils rock made of hardened sediment the time it takes for half of a radioactive sample to decay a way to determine which of two fossils is older
07_the_fossil_record_reading_guide.docx