Explanation of the UML arrows

Question

I have recently been studying UML and drawing simple diagrams with ordinary plain arrows between classes, but I know it\'s not enough. There are plenty of other arrows: gene

Answer 1

The accepted answer being said, It is missing some explanations. For example, what is the difference between a uni-directional and a bi-directional association? In the provided example, both do exist. ( Both '5's in the arrows)

If looking for a more complete answer and have more time, here is a thorough explanation.