According to the "principle of superposition of strata", the oldest rocks are formed at the bottom of sedimentary rock sequences.
The oldest rock layer would contain the the oldest fossil. Weathering, erosion, transportation and deposition would bring all sediments which includes rock materials and remains of living organisms to the basin where they would be lithified to form sedimentary rocks. This makes the oldest fossil to be at the bottom of the sequence. As time progresses, the fossil sequence would continue to accumulate and young upwards as the strata becomes relatively younger. Also, we know that fossils succeed one another in a definite manner.
This why relative dating of rocks can be possible.
coordinates the body's functions to maintain homeostasis during rest and exercise also to initiate and control movement, and all the physiological processes movement involves!
