Final answer:
The governments of Brazil and the United States are similarly structured with a president heading the executive branch in both nations, following the presidential system of government.
Step-by-step explanation:
The governments of Brazil and the United States are similar in that B) a president heads the executive branch. Both countries have a presidential system of government where the citizens elect the president to serve as the chief executive separate from the legislative branch. This separation of powers is essential to the way both governments operate, ensuring that the executive has a relatively limited role in the legislative process, and it can be categorized as a form of a representative democracy where citizens elect representatives, including the president, to promote their interests.