Answer:
Burning fossil fuels like coal and oil puts more carbon dioxide into our atmosphere. NASA has observed increases in the amount of carbon dioxide and some other greenhouse gases in our atmosphere. Too much of these greenhouse gases can cause Earth's atmosphere to trap more and more heat. This causes Earth to warm up.
Its definitely not A, nor is it D because food webs and food chains can be either land or aquatic animals. i think its B because a food chain goes up and a food web includes more organisms
The correct answer choice would be B. 4 acetyl CoA enter the citric acid cycle.
