Use the image below. Which fossil is a good example of an index fossil? (1 point)
Gastropod because it appears in multiple layers (long period of time) and in 3 columns (multiple areas)
O Gastropod because it appears in multiple layers (long period of time) and in 3 columns (multiple areas)
Ammonite because it appears in only 1 layer (limited time) but in 3 columns (multiple areas).
Trilobite because it only appears in one layer (limited time) and in one column (single area).