Consider the graph of carbon dioxide emissions by various fossil fuels in the United States.
From 1990 to 2017, which fossil fuel released the most amount of carbon dioxide into the air each
year?
Figure 3. Energy-related carbon dioxide emissions by fuel, 1990-2017

Oil

Explanation:

In the graph you can see that the bottom line corresponds to the emissions of the natural gas, the second line corresponds to the coal, and the top line corresponds to the emissions of the oil.

You can see that the emissions of the oil are always bigger than the other two, and never intersects them (it is always above the 2000 line). From this, we can know that the fossil fuel that released the biggest amount of carbon dioxide each year is the oil

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.