Fossils of marine organisms found high in the Andes Mountains led Darwin to conclude that:

• A. fossils can only be found in mountainous regions
• B. the Andes Mountains were formed by volcanic eruptions alone
• C. the region had once been underwater and was uplifted by geological processes
• D. marine organisms could survive at high altitudes

Answer: (C)

Verified step by step guidance

1. Understand the context: Fossils are the preserved remains or traces of organisms that lived in the past. Marine fossils specifically indicate organisms that lived in aquatic environments, such as oceans or seas.
2. Recognize the significance of finding marine fossils in the Andes Mountains: The Andes are a high-altitude mountain range, far from any current ocean. This suggests that the region's environment has changed significantly over time.
3. Apply geological principles: Geological processes, such as plate tectonics, can cause land to be uplifted. This means that areas that were once underwater can be raised to form mountains over millions of years.
4. Eliminate incorrect options: Fossils are not exclusive to mountainous regions; they can be found in various environments. The Andes were not formed solely by volcanic eruptions, and marine organisms cannot survive at high altitudes due to lack of water and suitable conditions.
5. Conclude: The presence of marine fossils in the Andes Mountains supports the idea that the region was once underwater and was uplifted by geological processes, such as the collision of tectonic plates.