Across
- 3. a fossil that is found a lot and is useful for dating rock
- 5. body parts that look similar, but may not have the same function
- 6. an unborn offspring before being born or hatched
Down
- 1. the study of how living things are put together (structure)
- 2. an earlier version of the living thing that was around before the modern day one
- 4. when an entire type of living thing is no longer alive anywhere in the world