Which of the following statements is true about Germany's use of U-boats?

i think the answer is a and i hope this ; ))

the growing interconnectedness of the world through communication, trade, and the exchange of ideas is an important theme in the history of the 20th and 21st centuries.

explanation:

these civilizations were located around fertile rivers, where they could produce an abundance of crops

in 1862, president lincoln's emancipation proclamation opened the door for african americans to enlist in the union army. although many had wanted to join the war effort earlier, they were prohibited from enlisting by a federal law dating back to 1792.

explanation: