What river cuts through the seven european countries including germany and austria

Can someone me with this plz? ! i'm putting 20 points on it!

The diagram shows , , and . which statement can be proven true from the diagram? a. ∠dgb is supplementary to ∠ega. b. ∠dgb is supplementary to ∠cgb. c. ∠cgb is supplementary to ∠agd. d. ∠ega is supplementary to ∠egc. e. ∠egd is supplementary to ∠cgb.

Short answer/constructed response: respond to the question in 3-5 complete sentences. give details or examples to support your answer. attempt to answer all parts of the question in paragraph form! using the source 1 map, pick two of the 1800's territorial acquisitions you believe were the most important in the development of the united states. provide at least two reasons per territory to explain why you think they were the most important.