Question

answer the questions about the diagram. organism a appears in the least outcrops. organisms a and b are the oldest. organism d would make the best index fossil.

Explanation:

Step1: Identify least - outcrop organism

Organism A is present in only one outcrop (Outcrop 1), which is the least compared to others.

Step2: Determine oldest organisms

A and B are found in the lower - most layers in their respective outcrops, indicating they are older.

Step3: Select best index fossil

An index fossil should be widespread and short - lived. Organism D is present in multiple outcrops and can help in correlating rock layers, making it a good index fossil.

Answer:

A. Organism A appears in the least outcrops. Organisms A and B are the oldest. Organism D would make the best index fossil.