I want to know about the relationship among construction companies, labor service companies, construction units and contractors. And the relationship between the economic director and the project mana

I want to know about the relationship among construction companies, labor service companies, construction units and contractors. And the relationship between the economic director and the project manager? Construction company: generally refers to a legal person enterprise qualified to undertake construction tasks.

Labor service company: generally speaking, it refers to a legal person enterprise that provides various labor services.

Construction unit: under this term, it refers to the corresponding units of the owner unit and the supervision unit, usually the team or organization authorized by the construction unit after winning the bid.

Contractor: it is a specific name for the contractor, which is generally reflected in the contract. The contractor is not necessarily a construction company or construction unit, but the construction unit must be a contractor.

Economic responsible person: as the name implies, it refers to a natural person who is responsible for project management and is directly responsible for project profits and losses.

Project manager: refers to the natural person authorized by the winning bidder to undertake the project management after winning the bid, and the specific responsibility scope depends on the authorized scope.