Plate boundaries where tectonic plates pull apart from each other are called:

A divergent boundary is a place where two tectonic plates move away from each other. As they separate, hot material from the mantle rises to fill the gap and forms new crust. For this reason, divergent boundaries are also called constructive boundaries.

Divergent boundaries in the oceans:

• Most divergent boundaries lie along mid-ocean ridges, long underwater mountain chains.
• Examples: the Mid-Atlantic Ridge, separating the North American and Eurasian plates in the north and the South American and African plates in the south; and the East Pacific Rise.
• New oceanic crust forms at these ridges, and the ocean floor slowly widens.
• Iceland sits on top of the Mid-Atlantic Ridge, so the ridge can be seen on land there; the island is being slowly pulled apart.

Divergent boundaries on land:

• When a continent starts to split, a long rift valley forms.
• The East African Rift Valley is a famous example, where the African continent is slowly splitting, possibly forming a new ocean in the distant future.
• The Red Sea and the Gulf of Aden are young oceans that formed where Africa and Arabia moved apart.

Features of divergent boundaries:

• Shallow earthquakes.
• Volcanic activity, mostly of runny basaltic lava.
• Rift valleys and mid-ocean ridges.

Three types of plate boundaries:

• Divergent (constructive): plates move apart; crust is created.
• A second type, where plates move towards each other, destroying crust or building mountains; it is covered in a separate question.

Transform (conservative): plates slide past each other horizontally; crust is neither created nor destroyed. Example: the San Andreas Fault in California.

Why not the other options?

• ✗Transform boundaries involve plates sliding past each other.
• ✗Hotspots, such as Hawaii, are places where plumes of hot mantle rise beneath a plate, not plate boundaries.
• ✗Fold belts are regions of folded mountains formed by compression.