Which of the following is a characteristic of most modern democracies?

Mandatory military service is not a common characteristic of most modern democracies. Many democratic nations have volunteer military forces rather than conscription, reflecting a choice-based approach to military service rather than a compulsory requirement imposed by the state.

In many modern democracies, particularly those with presidential systems, the government is not solely selected by the legislature. Instead, leaders are often elected directly by the populace, as seen in presidential elections, which emphasize voter choice rather than legislative appointment, differentiating them from parliamentary systems where the legislature selects the head of government.

Mandatory voting is not a standard feature in most democracies, although some countries enforce it. In many democratic systems, voting is a right and a voluntary act, allowing citizens the freedom to choose whether or not to participate in elections, highlighting the importance of personal choice in democratic processes.