Question

millions of years ago, tiny marine organisms died and sank to the ocean floor. over time, their remains decomposed into organic matter. this organic matter was buried deep underground, where intense heat and pressure transformed it into petroleum. the petroleum then became stuck in geologic traps and collected in reservoirs, from which humans have extracted it.
consider the following claim:
petroleum mostly formed in places that were once oceans.
which piece of evidence best supports this claim?
petroleum reservoirs are often found in limestone, a type of rock that typically forms in shallow marine environments.
petroleum is extracted by humans and used to make various fuels and other products.
petroleum formation involves intense heat and pressure deep beneath earths surface.
petroleum reservoirs are often found underground, contained within geologic traps capped by non - permeable caprock.

Explanation:

The claim is that petroleum formed in places that were once oceans. Petroleum reservoirs being often found in limestone (a rock that typically forms in shallow marine environments) directly links the formation location (ocean - related shallow marine) to the presence of petroleum. This provides evidence that supports the idea that the areas where petroleum formed were once oceanic (as limestone forms in such marine settings). Other options like petroleum formation involving heat and pressure deep beneath Earth’s surface, petroleum being extracted and used, or reservoirs being trapped by caprock do not directly relate to the claim about the location (once - ocean places) of petroleum formation.

Answer:

Petroleum reservoirs are often found in limestone, a type of rock that typically forms in shallow marine environments.