---
title: "Causes and impacts of World War I and II"
subject: "Technology, Environment and Society"
chapter: 3
key: "semester_7/technology_environment_and_society:world-wars-causes-impacts"
source: https://www.bctengineer.com/q/semester_7/technology_environment_and_society/world-wars-causes-impacts
site: BCT Engineering
---

# Causes and impacts of World War I and II

Technology, Environment and Society · Chapter 3: Brief History of Human Civilization

- Asked in: 2081 Bhadra, 4 marks
- Video: [Causes And Consequences Of World War 1 And 2 By Comparison](https://www.youtube.com/watch?v=28Qnd4XYISk) — Data Bi Data
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/technology_environment_and_society/world-wars-causes-impacts
- Whole chapter: https://www.bctengineer.com/md/semester_7/technology_environment_and_society/chapter-3

## Question

Describe about the causes and impacts of World War I and II.

## Short answer

WWI (1914–1918) was caused by militarism, alliances, imperialism, nationalism and the Sarajevo assassination; it collapsed empires, sparked the Russian Revolution and created the Versailles Treaty. WWII (1939–1945) stemmed from Versailles resentment, Depression, fascism, appeasement and the invasion of Poland, resulting in the UN, Cold War, decolonisation, nuclear weapons and 70–85 million deaths.

## Answer

#### World War I (1914–1918)

**Causes (MAIN):** **M**ilitarism (arms race), **A**lliances (Triple Alliance vs Triple Entente), **I**mperialism (rivalry for colonies), **N**ationalism; immediate cause: assassination of Archduke Franz Ferdinand at Sarajevo (28 June 1914).

**Impacts:** about 15–20 million deaths; collapse of German, Austro-Hungarian, Ottoman and Russian empires; Russian Revolution (1917); harsh Treaty of Versailles (1919); League of Nations (1920); new technology such as tanks, aircraft and submarines; women's role in work and voting rights increased.

#### World War II (1939–1945)

**Causes:** anger at the Treaty of Versailles, Great Depression (1929), rise of Hitler, Mussolini and Japanese militarism, failure of the League of Nations, appeasement; immediate cause: German invasion of Poland (1 September 1939).

**Impacts:** about 70–85 million deaths and the Holocaust; atomic bombing of Hiroshima and Nagasaki; United Nations (1945), IMF and World Bank; USA and USSR became superpowers and the Cold War began; decolonisation of Asia and Africa; Marshall Plan; technologies such as radar, jet engines, computers and nuclear energy.

| Point | WW I | WW II |
|---|---|---|
| Main cause | Alliances, nationalism | Versailles, fascism |
| Deaths | ~15–20 million | ~70–85 million |
| Peace body | League of Nations | United Nations |
| Result | Empires fell | Cold War, decolonisation |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What does MAIN stand for in the causes of WWI?
   A. Militarism, Alliances, Imperialism, Nationalism
   B. Money, Army, Industry, Navy
   C. Military, Allies, Invasion, Nations
   D. Monarchy, Anarchy, Industry, Nationalism
   Answer: A. MAIN is Militarism, Alliances, Imperialism, Nationalism. (Key point: WWI causes)

2. What was the immediate cause of WWI?
   A. German invasion of Poland
   B. Assassination of Archduke Franz Ferdinand at Sarajevo (1914)
   C. Pearl Harbor attack
   D. Russian Revolution
   Answer: B. The Sarajevo assassination on 28 June 1914 triggered the war. (Key point: WWI trigger)

3. Which matches the peace body created after each war?
   A. WWI: United Nations; WWII: League of Nations
   B. WWI: League of Nations; WWII: United Nations
   C. Both: League of Nations
   D. Both: United Nations
   Answer: B. League of Nations (1920) after WWI; United Nations (1945) after WWII. (Key point: Peace bodies)

## Related in Technology, Environment and Society

- [Short note: Impact of World War I and II](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Aworld-wars-impact-note) — Technology, Environment and Society, chapter 3, asked 2×
- [World wars impacts and population explosion](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Aworld-wars-population-explosion) — Technology, Environment and Society, chapter 3
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- [Economic, social and political impacts of WWII](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Awwii-impacts) — Technology, Environment and Society, chapter 3, asked 2×