Final answer:
Most members of the modern Congress are now professional politicians who typically seek to maintain their positions long-term, and Congress has become more descriptively representative, with increased diversity among its members, though it is still predominantly white and male.
Step-by-step explanation:
The modern Congress is different from the nineteenth-century Congress in that most members are now professional politicians who want to stay in Congress. This stands in contrast to earlier historical periods where political service might have been seen as a temporary or part-time endeavor. Today, members of Congress tend to view their roles as a full-time profession, with re-election being a significant focus of their activities in office.
Furthermore, the composition of Congress has become more descriptively representative of the U.S. population. The 117th Congress has seen increases in the percentage of racial and ethnic minorities, as well as female members, though Congress as a whole still does not completely reflect the demographic makeup of the country. Increased descriptive representation brings a variety of life experiences and perspectives to policy making, which can lead to better representation of constituents' interests.