Question

When the world war 1 started

Answer 1

Then earth will not exist in the universe.

Explanation:

Because, in now days many countries have nuclear weapons . so if world war happened one country bombarding on another country and another country on enemy country. it may be happening again and again earth will destroy many times.

Answer 2

$\tt\underline\red{answer : - }\\ \tt\purple{ \: \: \: \: World \: War \: First \: began \: in \: 28 \: july } \\ \tt \purple{ 1914 \:and \: it \: ends \: \: \:in \: \: 1918 \: and \: \: also \: } \\ \tt \purple{ World \: \: \: War \: \: \: Second \: \: \: \: began \: \: \: in \: \: 1 st\: \: } \\ \tt \purple{September \: \: \: 1939 \: \: and \: \: ended \: \: in \: \: 2 cd } \\ \tt \purple{ September \: 1945.}$