Read the following passage and answer the two items that follow. Your answers to these questions should be based on the passage only.
Crude mineral oil comes out of the earth as a thick brown or black liquid with a strong smell. It is a complex mixture of many different substances, each with its own individual qualities. Most of them are combinations of hydrogen and carbon in varying proportions. Such hydrocarbons are also found in other forms such as Bitumen, Asphalt and natural gas. Mineral oil originates from the carcasses of tiny animals and plants that live in the sea. Over millions of years, these dead creatures form large deposits under the sea bed; and ocean currents cover them with a blanket of sand and silt. As this mineral hardens, it becomes sedimentary rock and effectively shut out the oxygen, so preventing the complete decomposition of the marine deposits underneath. The layers of sedimentary rock become thicker and heavier. Their pressure produces heat, which transforms the tiny carcasses in to crude oil in a process that is still going on today.
Sedimentary rock leads to the formation of oil deposits because:
The passage explicitly states, "The layers of sedimentary rock become thicker and heavier. Their pressure produces heat, which transforms the tiny carcasses into crude oil." This indicates that the weight of the overlying sediment layers generates the necessary heat for the transformation of organic matter into crude oil.
Option (1): The passage does not mention saline conditions as a factor in the formation of oil deposits due to sedimentary rock. The explanation focuses on the physical processes of pressure and heat.
Option (2): The passage states that sedimentary rock "effectively shut out the oxygen, so preventing the complete decomposition of the marine deposits underneath." This directly contradicts the idea of dissolved oxygen entering the dead organic matter.
Option (4): The passage attributes the transformation to heat generated by pressure from sedimentary layers. It does not mention the presence of catalytic substances within the sedimentary rock that facilitate the chemical reactions for oil formation.