Hard
The following situation is not necessary in the formation of petroleum in nature by dead organisms-
Explanation
Explanation
Petroleum forms over millions of years when dead marine organisms get buried under layers of sediment, where they are subjected to high temperature, high pressure, and an oxygen-free (absence of air) environment, which slowly converts them into petroleum. The 'presence of water' on its own is not listed as one of the core necessary conditions for this conversion process — it's the heat, pressure, and lack of air that matter most. So the correct answer is presence of water, option (3).
PRO TIP
Re-check your working by substituting the answer back into the original question.