The diagram above shows a staff of rock layers examine the diagram and answer the question that follows layer key contains a well-known index fossil that is 120 years old layer are contains a different index fossil that is 100 million years old based on this information and the principle of superposition, how old is layer M is it younger than 100 million years either 20 million years or 220 million years older than 120 million years or between 100 million and 120 million years old
Based on the principle of superposition, layer M would be older than the layers above it but younger than the layers below it. Since layer M is below layer A, which contains an index fossil that is 100 million years old, we can conclude that layer M is older than 100 million years.
However, based on the given information, we cannot determine the exact age of layer M. It could be any age older than 100 million years, but it cannot be younger than 100 million years. Therefore, option C stating that layer M is older than 120 million years is incorrect.