Unicameral legislatures are popular in

Unicameral legislatures are most popular in countries that have a unitary system of government. A unitary system is a type of government where power is centralized in a single governing body, with lower levels of government, such as provinces or states, having little autonomy. In this type of system, a unicameral legislature, which means a legislature with only one chamber or house, is often sufficient to represent the entire population and make decisions on their behalf. On the other hand, in a federal system of government, power is divided between a central government and multiple regional or state governments, which means a bicameral (two-chamber) legislature is often used to represent the different levels of government. In a confederal system, power is even more decentralized, with individual states or regions having more autonomy than in a federal system, which means a unicameral legislature may not be able to adequately represent the interests of all the states or regions. Lastly, the use of a unicameral legislature is not related to the rigidity or flexibility of a government system, but rather to the degree of centralization and autonomy of the lower levels of government.