Which evidence predating plate tectonics supported the idea of continental drift?

• A. Radiometric dating alignment across continents.
• B. Matching coastlines, identical fossil assemblages across continents, similar rock units and mountain belts, and past climate indicators like glacial deposits.
• C. Current GPS measurements of plate movement.
• D. Magnetic reversals recorded in rocks.

Answer: (B)

Before plate tectonics was widely accepted, the strongest support for continental drift came from several clues that, together, suggested a single landmass in the past. The coastlines of continents like Africa and South America fit together almost like a jigsaw, which would happen if they were once joined and then split apart. In addition, identical fossils found on now-distant shores—animals and plants that couldn’t have crossed oceans easily—point to a common origin. The same goes for rock units and ancient mountain belts: if you trace the Appalachian mountains in North America, the Caledonides in Europe, and related rocks in Greenland and other places, they line up as if they were once one continuous range. Finally, evidence of past climates, such as glacial deposits and striations in now-tropical or temperate regions, implies those areas were located nearer the poles long ago and have since moved.

These lines of evidence together provide a coherent picture: continents were once connected, forming a supercontinent, and have since drifted apart. Other types of data, like modern GPS measurements, post-date the drift idea, and techniques such as radiometric dating or magnetic reversals contribute to understanding Earth’s history in different ways, but the pre-plate evidence described here is the classic bundle that supported continental drift.