4. Which system allows different regions to share power while the central government retains the right to determine matters of common concern? socialism unitary federalism confederate

## Step 1<br />The question is asking about a system of government where different regions share power, but the central government retains the right to determine matters of common concern. This is a description of a federal system of government.<br /><br />## Step 2<br />In a federal system, power is divided between a central authority and constituent political units, such as states or provinces. This division of power allows for a balance of power between the central government and the regional governments.<br /><br />## Step 3<br />The other options provided, socialism, unitary, and confederate, do not fit the description given in the question. Socialism is an economic system, not a form of government. A unitary system is a form of government where power is centralized in the national government, not divided among regional governments. A confederate system is a form of government where the central government is weak and the regional governments are strong, which is the opposite of what the question describes.