Why do scientists think South America and Africa were once joined?

• A. Their continental coasts could almost fit together
• B. They have identical climates today
• C. They have same number of volcanoes
• D. They have matching ocean floor age

Answer: (A)

The idea is that those continents were once part of a single landmass because their coastlines fit together like puzzle pieces, suggesting they were joined before drifting apart. But the fit isn’t just visual—the same rock types and mountain belts line up across the Atlantic, fossils of the same species appear on both sides, and there are clues from ancient climates and plant and animal fossils that point to a shared past in a different, joined location. Taken together, these lines of evidence support a single supercontinent that later broke apart as the tectonic plates moved. Climates today or the number of volcanoes don’t indicate a past connection, and patterns of ocean-floor ages reflect seafloor spreading and plate movement rather than proving a past land bridge.