Question

Select each correct answer. More than one answer may be correct.
Which of the following can scientists determine by comparing fossils from different layers of sediment?

exactly how many organisms were alive during a given time period
the order in which different types of organisms appeared on Earth
how different species have diversified over time

Answer 1

Correct answers: 2 and 3.

- Comparing fossils in different sediment layers gives the relative order in which organisms appeared (older layers = older fossils).
- It also reveals how groups changed and diversified over time (patterns of evolution and emergence of new forms).

It cannot tell exactly how many organisms were alive in a given period because the fossil record is incomplete.