Around 1920, the beginning of the era of public relations, pr companies began talking to people and listening to them when they talked backin other words, representing their various publics to their clients, just as they represented their clients to those publics.

Two-way communication.

Explanation:

Two-way communication, also called interpersonal communication is a method to transmit information between two individuals which saw its origins between the late 1880s and the early 1920s. Some well known examples of this kind of communication include conversations on the phone, chatting, radio contacts, and even face to face communication.

by improved communication.

b.

one company controls all the means of production of a product.

~coco