Answer:
The oil is considered as a fossil fuel because "it is non-renewable energy source"
Step-by-step explanation:
The non renewable resources are the one that are abundantly available and also they can be replenished quickly. Oil is formed deep inside the sea or ocean when the plants and the organisms gets decomposed after years of high temperature and pressure. This process takes millions of years to occur. In this process the anaerobic method of the degradation takes place. The content of carbon is more in the fossil fuels.