Oil comes from __________ that is pumped up from under the ground.

What word(s) goes in the blank?

resevoirs? pools? a number of words can go here.

The word that goes in the blank is "reservoirs".

To understand where oil comes from, we need to look at the process of oil formation. Oil is formed from the remains of ancient marine organisms such as algae and zooplankton. Over millions of years, the remains of these organisms accumulate on the ocean floor and get covered by sediment.

As more sediment layers build up, the organic matter undergoes heat and pressure, which transforms it into hydrocarbons. Hydrocarbons are compounds made up of hydrogen and carbon atoms, and they are the primary components of crude oil.

Once hydrocarbons are formed, they migrate through porous rocks, such as sandstone or limestone, until they reach a trap or reservoir beneath the Earth's surface. A reservoir is a porous rock formation that can hold significant amounts of oil or gas.

Oil companies use various methods, such as seismic surveys and drilling wells, to locate and access these underground reservoirs. When a well is drilled into a reservoir, the pressure underground forces the oil to flow up the well to the surface, where it can be collected and processed.

So, to summarize, oil comes from reservoirs that are pumped up from under the ground.