The image shows rock strata from three different regions on earth. identify all the layers that contain an index fossil

The correct answer is: Layer 1, layer 2, and layer 4 in all three regions.

The index fossils are fossils that are commonly used for identifying a geological period of time, and these fossils are also very wide spread, as well as having a rapid evolutionary trends.

By this picture, we can easily see that even though we have rock strata from different regions, the same layers contain the same fossil, and it is a fossil that also is rapidly evolving so has a minor change in each layer.

it is a

explanation:

the sphincter muscles at the end of the digestive tract is the anus.