Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period. Index fossils are useful because they tell the relative ages of the rock layers in which they occur.
Answer:
D
Explanation:
The G2/M check point makes sure that <u>all of the chromosomes have been replicated.</u>
- <em>Is all DNA replicated?</em>
- <em>Is all DNA damage repaired?</em>
Answer:
The control variable is the soldier.
Explanation:
The same soldier is used throughout the test
