Final answer:
Fossils can be used to study how species change over time. The age of fossils can be determined through relative and absolute dating methods. Radiometric dating is one method used in absolute dating to determine the numerical age of fossils.
Step-by-step explanation:
Fossils, or preserved parts of organisms from the distant past, can provide insights into how species change over time. The age of fossils can be determined through various methods, including relative dating and absolute dating. Relative dating involves comparing the position of fossils in rock layers, while absolute dating uses techniques like radiometric dating to determine the actual numerical age of the fossils.