What contributions to government and law were made by greece and rome?

The image below is a poster from world war i: image of poster that shows a hun soldier climbing out of the water. the following message is on the poster, beat back the hun with liberty bonds. public domain what was the main purpose of this poster? to create public distrust of germans to encourage young men to enlist in the army to demonstrate the reason for entering the war to generate financial support for the war effort