What can the presence of different types of fossils tell us about how this environment changed over time?
a. This environment has been an ocean from long ago through more recent times.
b. This environment has slowly changed from being an ocean to a swamp to a forest.
c. This environment has gotten much cooler over the period of time represented by these fossils.
d. This environment has become covered with water.
![What can the presence of different types of fossils tell us about how this environment changed over time a This environment has been an ocean from long ago thro class=](https://us-static.z-dn.net/files/d15/b001b7745809a57f7697c5fa7f39b4cd.png)