After the Second World War, the world was divided into two major power blocs. What were these rival blocs commonly called?

Introduction / Context:
This question belongs to modern world history and international relations. After the Second World War ended in 1945, global politics quickly shifted into the Cold War era, where two superpowers led competing alliances or "power blocs" that shaped world affairs for decades.

Given Data / Assumptions:
• Time period: Post-1945, after the Second World War. • Two dominant superpowers emerged: the United States of America and the Soviet Union (USSR). • Each superpower led a different ideological and military bloc.

Concept / Approach:
After the war, the United States led the Western, capitalist and often democratic bloc, supported by organisations like the North Atlantic Treaty Organization (NATO). The Soviet Union led the Eastern, communist bloc, including many countries in Eastern Europe grouped in the Warsaw Pact. These two groups are typically referred to as the capitalist bloc and the communist bloc, or the Western and Eastern blocs.

Step-by-Step Solution:
Step 1: Identify the key superpowers after the Second World War: USA and USSR. Step 2: Recall that the USA promoted capitalism and liberal democracy. Step 3: Remember that the USSR promoted communism and a centrally planned economy. Step 4: Recognise that allied states grouped themselves around these two ideologies, forming rival power blocs. Step 5: Choose the option that clearly names these blocs as the capitalist bloc and the communist bloc.

Verification / Alternative check:
Cold War history in any standard textbook describes the USA-led Western bloc as capitalist and the USSR-led Eastern bloc as communist. They competed militarily, economically and ideologically but rarely fought each other directly. Instead, they engaged in proxy wars and an arms race. This confirms that "capitalist bloc and communist bloc" is the accepted description of the two power blocs.

Why Other Options Are Wrong:
Option Asian bloc and European bloc: Countries in each bloc were spread across multiple continents, not just Asia or Europe. Option Colonial bloc and Non-colonial bloc: The conflict was ideological, not simply based on colonial status. Option Northern bloc and Southern bloc: This oversimplifies geography; many allies of each superpower were located in both hemispheres. Option League of Nations bloc and UN bloc: The League of Nations was replaced by the United Nations and did not form a Cold War power bloc.

Common Pitfalls:
Students sometimes confuse geographic labels like "East" and "West" with continents themselves. Remember that "Western bloc" meant U.S.-aligned capitalist democracies, while "Eastern bloc" meant USSR-aligned communist states, many of which were in Eastern Europe but also in Asia and other regions. Linking each bloc with its leading ideology and superpower helps avoid confusion.

Final Answer:
Therefore, the two power blocs that emerged after the Second World War were the capitalist bloc and the communist bloc.