Assembles parts of the component which was provided by other contractors
Explanation:
With a modular structure, A firm contacted many supplies to produce or make a or some certain components of a product on the firm behalf, in which the firm would take further steps in assembling the components made by other supplies to produce or integrated to make a particular product, this was the case in regards to the massive 787 Dreamliner project.
A modular structure can be refers to a structure or product that can be group/detached or separated and later assembled to form a single product.
Unrestricted submarine warfare is a type of naval warfare in which submarines sink merchant ships and tankers without warning. I don't know what you want for an example, but Germany used it in World War 1.