Arrange in chronological order the formation of petroleum and natural gas. Write letters A-D in the space provided before each number that shows the correct order.

___. Layers of silt, sand and rocks and drilled today to reach the layer where oil and gas deposits contains.

___. Marine plants and animals lived million years ago, died and buried on the ocean floor.

___. As the remains of the dead organisms buried deeper and deeper over millions of years, it experienced the extreme heat and pressure underneath that turned them into oil and gas.

___. There remains were covered by layers of san and silt over time.​

The answer is:
C
A
B
D