Question

Use the image below. Which fossil is a good example of an index fossil?



(1 point)
Responses

Ammonite because it appears in only 1 layer (limited time) but in 3 columns (multiple areas).
Ammonite because it appears in only 1 layer (limited time) but in 3 columns (multiple areas).

Gastropod because it appears in multiple layers (long period of time) and in 3 columns (multiple areas)
Gastropod because it appears in multiple layers (long period of time) and in 3 columns (multiple areas)

Trilobite because it only appears in one layer (limited time) and in one column (single area).
Trilobite because it only appears in one layer (limited time) and in one column (single area).

Fern because it appears in multiple layers (long period of time) and in 3 columns (multiple areas)
Fern because it appears in multiple layers (long period of time) and in 3 columns (multiple areas)
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Answer 1

To identify a good example of an index fossil, we look for a fossil that has a limited time range (appears in only one layer) but is found in multiple geographic areas (represented by multiple columns).

Based on the provided options:

1. **Ammonite**: Described as appearing in only one layer (limited time) and in three columns (multiple areas). This makes it a good candidate for an index fossil.
2. **Gastropod**: Appears in multiple layers (long period of time) which is not ideal for an index fossil.
3. **Trilobite**: Appears in only one layer (limited time) but in only one column (single area), which does not meet the geographic distribution criterion.
4. **Fern**: Appears in multiple layers (long period of time), which again is not suitable as an index fossil.

**The best answer is: Ammonite because it appears in only 1 layer (limited time) but in 3 columns (multiple areas).**