Amphtracs helped the marines land more safely on Pacific Islands by being able to successfully land on the beaches themselves, instead of stalling out on the reefs as many conventional landing craft did.
Step-by-step explanation:
Because of the Convoy system U.S won the battle of Atlantic and when the U.S boats fired at American ship the destroyers who are in the boat would sink the U.S boat. Freighters travel with military ship as they have supply of ships. Death was certain if the submarine fired.
During world war II at the time of pacific war military strategy was applied against Japan. They captured the island and create military base over there. Then the base was used for launching and take over the weapons for further attack.