Why is crude oil an important natural resource?
There are two main reasons. First off, crude oil has a lot of energy tied up in it; if you process it, and burn it in an engine, you can use a little bit of oil to get a lot of work done. Cars mostly use gasoline and diesel as fuel, and both of those are processed from crude oil. Secondly, the shape of the molecules in crude oil makes them very useful for manufacturing. Nearly all plastics, including things like packing plastic, drinking cups, and Styrofoam, are created from crude oil; the molecules (called “polymers”) tend to stick together in long and springy chains. This lets us make flexible materials that can often take a lot of punishment before breaking.
It will be hard to beat Greymav’s answer, there are other energy sources, other raw materials for fabrication, but there may be no SINGLE source that is so flexible, easily obtained stored and processed as oil. We’re working on replacements but often you need to use multiple different approaches to replace what can be made from oil (wind can make electricity but not plastic, fuel made from corn actually gets lower mpg, etc.). Plus it has the advantage of time- even if we found one substance to replace oil we have a century of infrastructure (from power stations to personal cars) we’d have to replace too.
