What is the difference between 'includes', 'extends' and 'uses'?

Question

In a use case diagram what is the difference between <>, <> and <>? Are

Answer 1

The include relationsionship is usually used in use cases to signify that one use case uses the other. In contrast the use relationship is used in UML to show dependencies between models, that one model requires the other in order to function.

Here are the quotes from IBM's documentation.

Include relationships
In UML modeling, an include relationship is a relationship in which one use case (the base use case) includes the functionality of another use case (the inclusion use case). The include relationship supports the reuse of functionality in a use case model.

Usage relationships
In UML modeling, a usage relationship is a type of dependency relationship in which one model element (the client) requires another model element (the supplier) for full implementation or operation.

To recap (as I understand it) includes is a dependency in the model while use is a dependency in the functionality.