Answer:
- Not all organisms are fossilized.
- Not all fossils survive.
- Not all fossils are found.
Step-by-step explanation:
The most direct way to determine the age of a species is to observe in the fossil record what was the first occurrence of this species. The biggest problem is that the fossil record is very incomplete, because many times organisms decompose before being fossilized, and many fossils have never been found. In short, we can say that the fossil record is incomplete because not all organisms are fossilized, not all fossils survive and not all fossils are found. Moreover, the fact that one finds fossils of a species from a certain age does not mean that such a species originated at that time in geological history. It may be that records of the species's presence in previous ages have been lost.