fossils are of organisms known to have existed during a certain time period and are relatively abundant, assisting scientists in dating rocks and fossils within them. Absolute dating of fossils and rocks takes advantage of radioactive within the fossils or rocks and their decay. We are living during the Cenozoic era and the Holocene . Respond to the following based on your reading. Why is an index fossil so important for the fossil record? Order the geologic time periods from smallest to largest. Why is this organization important? In which era did human beings evolve? How old are the oldest fossils? What's the difference between relative and absolute dating?

1. Index

2. isotopes

3. epoch

4. An index fossil is known from a specific time period, is prevalent, and has had many fossils formed. This allows for recognition of similar time periods in different geographic locations.

5. The geologic time periods from smallest to largest are epoch, period, era, and eon. This organization is important because it allows us to describe and classify the evolution of living things on Earth.

6. Human beings evolved during the Cenozoic era.

7. The oldest fossils are estimated to be 3.5 billion years old.

8. Relative dating compares the ages of fossils and rocks relative to one another in a specific area to determine which are older and which are younger. Absolute dating applies a specific time period or age to the fossils and rocks.

Explanation:

Penn Foster

one characteristic that is shared by all is a soft body. many

of these invertebrate animals also have an outer shell to protect their

body. oysters, clams, snails, and mussels are all mollusks. so are octopuses, squids, and slugs. mollusks live on land and in freshwater.