What type of fossil evidence would be most helpful to a scientist trying to determine how much oxygen was in the atmosphere two million years ago?

A) Ice Cores
B) Tree Rings
C) Carbon Films
D) Trace Fossils

Which sequence correctly shows the path of carbon dioxide during repiration?

How do you date a sample of rock that you suspect as being one of the earliest on earth

Rarefaction is used for which of the following? a. creating a representative sample b. studying how disease impacts populations c. rediscovering species thought to be instinct d. determining which sea creatures live in an area