Part 3/10:
Historically, the criteria for defining a continent focused primarily on geographical size and presence of land, but with significant advancements in geological understanding since the 1960s, distinctions became clearer. It was established that there are two types of crust: oceanic and continental. This understanding led scientists to realize that continental crust—which is predominantly composed of granite—is less dense and ‘floats’ higher compared to the denser, basaltic oceanic crust.