Question

12.trench warfare – a type of land combat where opp fight from systems of deep,fortified ditches dug
13.no man’s land – an unclaimed,uninhabited,or ambig
14.u-boat –
15.lusitania –
16.zimmerman telegram –
17.woodrow wilson –
18.treaty of brest-litovsk –
19.armistice –
20.treaty of versailles –
21.fourteen points –

1. league of nations –

Explanation:

To answer these questions, we'll provide brief explanations for each term related to World War I history (a subfield of History within Social Science):

14. U - Boat

German submarines in WWI, used for naval warfare, including unrestricted submarine warfare that targeted merchant and passenger ships, like the Lusitania.

British passenger liner sunk by a German U - Boat in 1915. The sinking, which killed many civilians (including Americans), contributed to growing anti - German sentiment and was a factor in the US's eventual entry into WWI.

A secret German telegram (1917) to Mexico, proposing a military alliance against the US. Intercepted and decoded, it was a major reason for the US to enter WWI on the Allied side.

Answer:

German submarine used in WWI, for naval warfare (including unrestricted submarine attacks).

15. Lusitania