What information can a scientist learn directly from a single fossil?

There are many things, which scientists can learn directly from a fossil, some of them are as follows:  

1. One can know about that when some groups of animals got evolved and who were their ancestors.  

2. One can become familiar with the kinds of organisms thrived at what times and where they lived.  

3. One can know something regarding the species, which no longer lives, comprising what they ate, their appearance, and other kinds of traits.  

4. One can know more about the drifting of continents by comparing it with the places where the fossil species have been found.  

i am going to guess that it is co2.

i think that it is plants