Only animals turn into fossils. Plants do not form fossils.
It is a very complicated process for animals/plants to turn into fossils.
Everything does turn into a fossil, they are just very hard to find.
Many animals/plants are destroyed before they can turn into a fossil.
Both a and c.
Both b and d.
Information about the past environment.
Where animals came from.
What animals from the past looked like.
All of the above.
Mold and cast
All types of rock, it doesn't matter