What is the primary feature of a divergent boundary?

The primary feature of a divergent boundary is the creation of oceanic ridges. At these boundaries, tectonic plates move away from each other, allowing magma from the mantle to rise up and solidify, forming new oceanic crust. This process contributes to the development of mid-ocean ridges, which are underwater mountain ranges. As the plates pull apart, volcanic activity frequently occurs, and this activity not only shapes the seafloor but also contributes to the growth of the ocean basin.

While the formation of rift valleys can occur at divergent boundaries, particularly on continental landmasses, it is typically associated with continental divergence rather than oceanic divergence. Similarly, mountain ranges and the destruction of oceanic crust are more characteristic of convergent boundaries, where plates collide or one plate is forced beneath another. Thus, the creation of oceanic ridges is the key geological feature associated with divergent boundaries, making it the correct answer.