| A | B |
|---|
| The geologic time scale was developed by scientists using the ________________. | Fossil record |
| Geologic time is divided into eras and ____. | periods |
| Precambrian time accounts for ______ % of earth's history. | 88 |
| Which best describes the geologic time scale? | It presents the correct sequence of events in Earth’s history. |
| Which statement about life on Earth is true? | Humans have been on Earth for a very short amount of time. |
| How old is the earth? | 4.6 billion years old |
| The geologic time scale was created by scientists who studied ______ layers and index fossils. | rock |
| The longest period of time on the geologic time scale is ___. | Precambrian |
| How do scientists think the moon formed? | The earth ran into an object and it threw material into orbit. |
| Why is the ozone layer important to living things on earth? | It blocks ultraviolet rays from the sun. |
