1. Divergent Boundaries:

* What happens: Plates move apart, allowing magma from the mantle to rise and form new crust.

* Features:

* Mid-ocean ridges (underwater mountain ranges)

* Rift valleys (land-based valleys)

* Volcanoes (often basaltic)

* Earthquakes (generally shallow)

* Examples:

* Mid-Atlantic Ridge

* East African Rift Valley

2. Convergent Boundaries:

* What happens: Plates collide, with one plate subducting (diving) beneath the other.

* Features:

* Trenches (deep depressions in the ocean floor)

* Volcanic arcs (chains of volcanoes)

* Mountain ranges (formed by folding and faulting)

* Earthquakes (ranging from shallow to deep)

* Types:

* Oceanic-Continental: Oceanic plate subducts under continental plate (e.g., Andes Mountains)

* Oceanic-Oceanic: One oceanic plate subducts under another (e.g., Mariana Trench)

* Continental-Continental: Two continental plates collide (e.g., Himalayas)

3. Transform Boundaries:

* What happens: Plates slide past each other horizontally.

* Features:

* Transform faults (breaks in the Earth's crust where movement occurs)

* Earthquakes (often shallow and powerful)

* No volcanic activity

* Examples:

* San Andreas Fault (California)

* Alpine Fault (New Zealand)

It's important to note that these are simplified descriptions, and the real world is more complex. For example, there are often zones of transition between different types of boundaries, and the exact processes involved can vary significantly.