What do scientists believe is the origin of crude oil?

Scientists widely believe that the origin of crude oil is primarily linked to marine organisms, such as microscopic plankton, algae, and other aquatic life forms that thrived in ancient oceans. Over millions of years, these organisms accumulated on the seabed and were buried under layers of sediment. The combination of heat and pressure over geological time transformed this organic material into hydrocarbons, which are the main components of crude oil.

This process, known as diagenesis, occurs in anoxic conditions (low or no oxygen), which prevent the complete decomposition of the organic material, allowing it to be preserved and eventually converted into oil. The specific conditions of the marine environment, including the presence of suitable sedimentary rocks and appropriate temperature and pressure, are critical for the formation of oil reserves we extract today.

The other options suggest different origins that lack supporting geological evidence. For example, while terrestrial plants contribute to some fossil fuels, they are not the main source of crude oil. Volcanic activity does not produce hydrocarbons and typically relates to magma and mineral formation rather than organic compounds. Similarly, while dinosaurs are a prominent theme in popular culture, they represent a very small fraction of the organic matter converted into oil; most crude oil originated from much smaller marine organisms that pre