Ascientist who researches the age of rock layers in the grand canyon studies science. a. earth c. physical b. life d. applied

a. earth

Explanation:

A scientists that is interested and is studying rock layers studies a and earth science. More specifically, the scientists that would do this is most probably a geologists, which is one of the branches of geography.

The geology is focused on the rock strata. The formation of it, its origins, its development, destruction, the processes happening to it or from it. The geology is part of the physical branch of geography, thus it is and earth science as it studies the physical forms of Earth.

Through this type of sciences and their researches, we get information about the development of our planet. How the rocks came to be, how they evolved over time, and what was the cause o f it. Also, the researching of the rocks provides lot of other information about the Earth, as the rock strata often contains fossils, evidence about the climate, dramatic events that have happened on Earth etc.