What can be determined from examining the fossil record?

a. when changes to the diversity of life forms occurred
b. when many life forms first appeared on earth
c. when many life forms became extinct
d. all of the above

D. all of the above

Explanation:

The fossil records are of great importance for providing evidence about the evolution of the species, as well as the environment in which they lived. The fossils are able to give us clues about when the life occurred on Earth, when it started to diversify and what kind of conditions. The fossils also give us approximate time of when a species has appeared, and approximately when that species had gone extinct. Apart from these information, the fossils are giving the scientists the material from which they can recreate the living organisms, how they lived and behaved, thus being able to reconstruct the past of our planet.

a corroding iron, if that's one of your choices