Final answer:
The designated or managing broker is generally responsible and liable for the actions of all real estate licensees in a real estate firm.
Step-by-step explanation:
The individual responsible and liable for the actions of all real estate licensees conducting business in a real estate firm is typically the designated broker or managing broker. This individual holds the legal authority to oversee the professional conduct of the salespersons and associates within the firm. They ensure that the firm and its agents comply with all state real estate laws and regulations. The brokerage has the responsibility to ensure that its agents act in accordance with professional and ethical standards. It is the broker's duty to supervise their agents and to bear the consequences of any professional lapses their agents might make.