They show that there was an ocean over the plains long ago, and fossils are always used to elaborate on the history of life/how it developed.
I believe it is the first answer
hope this helps
Answer:
The sun, or abiotic factors
Explanation:
Primary producers are organisms that make their own food, such as plants. They do this through photosynthesis, which requires sunlight, water, and carbon dioxide.
In the Northern Hemisphere, for example, predictable winds called trade winds blow from east to west just above the equator. The winds pull surface water with them, creating currents. As these currents flow westward, the Coriolis effect—a force that results from the rotation of the Earth—deflects them. The currents then bend to the right, heading north. At about 30 degrees north latitude, a different set of winds, the westerlies, push the currents back to the east, producing a closed clockwise loop.
Hope that helped :D