Question

Which among the following is true in the case of sedimentary rocks?
A. Upper strata older and lower younger
B. Upper strata younger and the lower older
C. There is no stratification
D. None of the above

Answer 1

Hint: When an organic matter is decomposed, it starts to form layers over it of minerals, organic matter etc. with the help of water, air currents. So the rocks formed over time will have layers of substances from different periods. They help us to study evolution.

Complete answer:
What are sedimentary rocks? These are the rocks formed after the deposition of the small particles, minerals, organic particles on the floor of the oceans or other water bodies. They are made from the pre-existing pieces of living organisms
Option A: Upper strata older and lower younger: While their shaping, molten rocks are more youthful. As the sedimentary shakes, they move down, below the sedimentary layer. Thus the fresh younger layers come at the bottom and the upper becomes older.
Option B: Upper strata younger and the lower older: This is incorrect as the molten rocks move the lava eruption seep down the sedimentary rocks forming a younger layer at the lower level.
Option C: There is no stratification: Stratification means layering. We know that the sedimentary rocks are formed over time so the deposits on them form a layer from time to time, giving it a stratified look. So the sedimentary rocks have stratification.

So the answer is option A: Upper strata older and lower strata younger.

Note:
Layering or stratification is mostly seen in igneous and sedimentary rocks. The volcanic eruption (lava) flows over them to deposit the volcanic deposits. They can vary in thickness. This is a result of the difference in the densities of the layers, temperature, salinity etc. it occurs mostly in the summer season.