Explanation:

- Simple System: The barter system is straightforward. People simply exchange goods or services that they have for goods or services they need, without involving complex transactions or currencies.

- More Mutual Co-operation: Participants in a barter system often have to communicate and negotiate directly. This can foster relationships and increase mutual cooperation and understanding between them.

- No Economic Disparities: In a barter system, the wealth isn't concentrated as it can be with money. Everyone exchanges what they have in a way where they perceive equal value, theoretically reducing economic disparities.

- All the above: Given the explanations above, each point is indeed an advantage.