Divergent boundary:the boundary between two tectonics plater that are moving away from each other.
Example:the boundary between Arabian plate and African plate at Red sea.
Rift valley
Rift valley :a large elongated depression with steep walls formed by the downward displacement of a block of the earth's surface between nearly parallel faults or fault systems.
Rift valley real world example...
Mid-ocean ridge
Mid-ocean ridge: a general term for an underwater mountain system that consists of various mountain ranges, typically having a valley known as a rift running along its spine, formed by plate tectonics.
Mid-ocean ridge real world example.