In a parliamentary system, the opposition party plays several crucial roles. First, it acts as a check on the ruling party, holding it accountable by challenging policies and decisions. This includes participating in debates and question periods to scrutinize governmental actions. Second, the opposition develops alternative policies and agendas to present to the public, providing voters with choices at elections. Third, it can mobilize public support for issues it champions. Lastly, the opposition fosters a pluralistic political environment by ensuring diverse viewpoints are represented in parliamentary discussions.