Answer:
<h3>Team sports tend to be tactical sports, there is needed strategies, techniques and tactics to achieve victory.</h3>
Offensive and defensive roles are tactical positions towards an strategy implementation. This roles are important because players can specialised on the unique tasks in order to achieve the best performance for the team, sacrificing their skills in other areas.
Offensive roles are positioned in front of the team, they are the ultimate executors of the strategy, they need to be precise on his techniques to ensure the success. Also, they play agains defensive positions, which are going to try to stop them.
On the other hand, defensive roles have different skills than offensive position. Their job is to protect the strategy from offensive players. A strong defense can ensure the success of the strategy.
So, basically, these roles are the contrary each other. Some teams emphasise strategies base on high skill defence, other teams prioritise a perfect offensive. Either way will ensure victory, must of the time depends more on the strategy applied.