Final answer:
The governments of Brazil and the United States are similar in that a president heads the executive branch of the government.
Step-by-step explanation:
In both Brazil and the United States, a president heads the executive branch of the government. This means that the president is the chief executive and is responsible for overseeing the implementation and enforcement of laws. However, the other options mentioned in the question are not similarities between the governments of Brazil and the United States. Voting is not required by law in either country, and political parties in Brazil and the United States have different processes for selecting presidential candidates. Additionally, in both countries, the legislative branch is not appointed by the judicial branch.