The first blank can be filled with divergent. The mid-ocean ridges and rift-valleys are essential characteristics produced along a divergent boundary. A divergent boundary refers to a linear characteristic, which prevails between two tectonic plates that are parting away from each other.
The second blank can be filled with a transform boundary. A plate boundary, where the motion is predominantly horizontal is known as a transform boundary or transform fault. The San Andreas fault is a transform boundary where plates slide horizontally past each other, producing many earthquakes.
The third blank can be filled with convergent boundary. The convergent plate boundary is formed when two tectonic plates collide. Generally, one of the converging plates will move underneath the other that is called subduction. Deep ocean trenches are generally produced where tectonic plates are being subducted and earthquakes are a usual feature.