Which statement best describes the relationship between continental formation around 3.5 Ga and the later development of life on land?

• A. Complex life on land flourished immediately after continents formed
• B. Continents formed around 3.5 Ga and complex land life formed much later
• C. Continents formed after complex land life had flourished
• D. Continents never formed by 3.5 Ga

Answer: (B)

The key idea is the timing gap between when continents formed and when complex life could live on land. Continental crust stabilized very early, around three-and-a-half billion years ago, creating landmasses that would persist for geological time. Life, however, began in the oceans as simple, single-celled organisms, and it took a long path—development of land plants, soils, and a habitable atmosphere—to enable complex life to colonize the land. Fossil and rock records show land plants arise hundreds of millions of years later, followed by land animals, well after continents were already in place. So the statement that continents formed around 3.5 Ga and complex land life formed much later best reflects this sequence.