Final answer:
The black market is characterized by illegal economic activities and transactions while the informal market involves unregulated but not necessarily illegal activities, such as under-the-table jobs or small unregistered businesses.
Step-by-step explanation:
The black market refers to economic activity that is illegal and conducted without the sanction of the government. This might include the trade of illegal goods, such as drugs or unlicensed firearms, or the evasion of taxes and tariffs. In contrast, the informal market involves business activities that are not officially recognized or regulated, but aren't necessarily illegal. This includes the work of individuals like under-the-table nannies, gardeners, or informal businesses operated from homes such as daycares or salons.
While both markets exist outside of governmental oversight, the black market is characterized by its illicit nature, whereas the informal market is often made up of self-employed individuals or small businesses operating in a state of imperfect information, without the protections and regulations that formal employment provides.