Civil wars are fought between citizens of the same country，and are fought within the waycountry
If citizens of country disagree about a policy or leader，they may fight a civil war
A world war is fought when countries form alliances and these alliances fight each other
There were 2 world wars in the 20th century
Terrorism involves groups of individuals rather than countries
Terrorists can come from different countries ，and they may share the same beliefs
Terrorists often use car-bombings and suicide attacks on innocent people
A terrorist attack can happen at any time and any place
An invasion occurs when one country attacks another
It sends its army into the other country and attempts to take control
One of the most famous invasions wad when France invaded Russia in 1812
A defensive war occurs when a country is attacked and needs to defend itself
Most contries have a military，so that it can defend itsself if it's attacked
When France invaded Russia in 1812 the Russia army fought a defensive war and defeated the France army
