Explanation:

Bicameralism is the practice of having two legislative or parliamentary chambers. Some countries, such as Argentina, Australia, Austria, Belgium, Bosnia and Herzegovina, Brazil, Canada, Germany, India, Malaysia, Mexico, Pakistan, Russia, Switzerland, Nigeria, and the United States, link their bicameral systems to their federal political structure. Many bicameral countries like the Netherlands, the Philippines, the Czech Republic, the Republic of Ireland and Romania are examples of bicameral systems existing in unitary states. In countries such as these, the upper house generally focuses on scrutinizing and possibly vetoing the decisions of the lower house. In a few countries, bicameralism involves the juxtaposition of democratic and aristocratic elements. Hence, all options are correct.