Describe how the relative age of a rock layer is different from the actual age of the rock layer

The relative age of a rock layer is the age of the rock compared to the ages of the rock layer while the actual age of the rock layer is the actual number of years that the rock was formed.  The relative age of a rock is generally determined by geologists using the Law of Superposition where the youngest rock is at the top and the oldest rock is at the bottom of the horizontal layer. The actual age of a rock is generally determined using Radiometric Age Dating method that is based on the natural radioactive decay of rock elements.

The answer is joseph is observing the colour of the reaction mixture to see whether proteins are present in the given solution.