Answer:
c. fossils
Explanation:
Fossils are the remains of dead and decayed organisms that are preserved in rocks. Fossils can be preserved using their hard parts, or the products of their activities can remain still for several years.
Fossil are used for relative age dating of rocks. According to the principle of fossil and fauna succession, it is scientifically correct to correlate areas with the same fossil record because fossils succeed on another in a definite order. All rocks that exists in that time period will contain the organisms that lived during that period in time.
The correct answer is B. Less arable land.
Arable land is the main reason why the land is cleared. Arable land is the land that is suitable for ploughing and of sufficient quality for growing plants. So for this reason, the forests are cleared (by cutting the trees and bushes) and more land for agriculture is gained.
Our energy supply comes mainly from fossil fuels, with nuclear power and renewable sources rounding out the mix. These sources originate mostly in our local star, the Sun.
A valley ca be formed by flowing water from a river.