Final answer:
The most frequently used method to investigate sediment and rock layers of the sea floor is sound waves, or seismic surveying. This non-invasive method allows for a comprehensive understanding of subsurface features, aiding in geological research and exploration.
Step-by-step explanation:
The method that is most frequently used to investigate sediment and rock layers of the sea floor is (e) sound waves. This technique, known as seismic surveying, involves sending sound waves into the sea floor and then recording how they reflect back to the surface. The patterns of reflectivity can help geologists identify various characteristics such as rock types, deformation features, and potential locations of water or petroleum. The data obtained from these surveys is vital for advancing our understanding of subsurface stratigraphy and for supporting various geological studies, such as identifying marine fossils in different layers or understanding Earth's plate boundaries.
Drilling, like that performed by the International Ocean Discovery Program (IODP), is another method used to directly examine seabed samples. However, seismic surveying allows for a wider and more comprehensive view of the subterranean landscape before other methods are employed. The use of seismic waves is akin to medical ultrasound imaging, where the internal structure is visualized without physical intrusion.