The Earth is approximately 4.6 billion years old. How much of this time is considered to be Precambrian time?
10% of Earth's History
90% of Earth's History
All of the time after the dinosaurs extinction
All of the time since the big bang
Which of the following statements represents the absolute age of the subject?
Fossil A is older than Fossil B
Fossil C is 50 million years old
Fossil D is older than the last mass extinction
There is no way of determining absolute age
The fossil found in level C is estimated to be 40,000-50,000 years old. Therefore, the fossil found in level D must be...
20,000 - 40,000 years old
50,000 - 70,000 years old
75,000+ years old
The same index fossil is found in rock layers A and B that are separated by several miles. What can you infer about the relationship between the rock layers?
Layer A is older than B
The sediments in layer B were deposited before those in layer A
Layers A and B are probably about the same age
Layer B probably contains more radioactive isotopes than layer A
If a sample of Carbon-14 starts with 500 atoms, how many would there be after one half-life?
500
250
125
75
If the half-life for the sample above is 2,000 years, how old is the sample when there is 25% of the parent element remaining?