Which fossil fuel has had the most significant influence on human transportation over the last centrury?

Oil is the world's primary fuel source for transportation

Explanation:

Fossil fuels mainly coal, Oil and natural gas are the world's primary energy source. Fossil fuels formed from Organic matter over millions of years.

Oil is a source of transportation and it is obtained from the underground reservoirs. Then the crude oil is refined to obtain fuel oil, liquid petroleum, gasoline etc. Crude oil also used to make other products such as pesticides,fertilizers etc

Coal is used to generate electricity. Around 30% of the power supply in United states mainly due to coal. China is world's largest producer of coal and supplied to all over the World.

Natural gas also used to generate electricity, commonly used in buildings and industries.

i think its the first one

i don't know. if i were you, i would search it up online : d