Respuesta :
The horsehoe crab because it was one of the first animals to ever live on earth
Answer;
Pigs would be more useful as an index fossil.
Explanation;
- An index fossil is an animal or plant that is preserved in rock record of the earth and has a characteristic of a certain period of geologic time or environment. A useful index fossil must be abundant, easily recognizable, and have a geographic distribution.
- Pigs would be a useful index fossil because the well-documented changes that occurred in the fossil record would help geologists determine the ages of rocks much more than the unchanging horseshoe crabs.