Question

which discovery did scientists make at mid - ocean ridges that caused them to conclude that new rock was being formed by molten material?
magnetic banding
pillow - shaped rocks
older rocks farther from the ridge
rocks with similar characteristics

Explanation:

Pillow-shaped rocks form when molten magma erupts underwater (like at mid-ocean ridges) and cools rapidly, creating a rounded, pillow-like structure. This direct geological feature is evidence that molten material is solidifying into new rock at these ridges. Magnetic banding relates to polar reversal patterns, older rocks farther from ridges supports seafloor spreading rate, and similar rock characteristics are not specific to molten rock formation here.

Answer:

pillow-shaped rocks