Explanation:

- Collective conscience: This refers to the set of shared beliefs and moral attitudes which operate as a unifying force within society. It is more characteristic of traditional societies.

- Collective representations: These are concepts, symbols, and ideas shared by a society, representing communal life and thought.

- Mechanical solidarity: Found in traditional and small societies, this is social cohesion based on shared beliefs and similarities.

- Organic Solidarity: This is characteristic of modern, industrialized societies. It's a form of social cohesion based on the interdependence of individuals performing specialized roles.

Organic Solidarity is indeed considered a pre-requisite for modern economic development according to Durkheim.