Last one because everyone started building navies, so everyone else started building navies in order to defend against other navies.
Answer: To show loyalty to the U.S., gain upward mobility and/or Citizenship
Explanation: During World War II, many Americans of Japanese descent volunteered to join the U.S. military. This was in spite of growing sentiments against them as well as internment of Japanese Americans in camps.
It was a way to show loyalty to the U.S. For some it was the only way to gain citizenship, as well as move up the social ranks as ethnic minority groups had limited rights. They were first rejected, with the exception of bilingual Japanese Americans who helped with translation and interrogation.
West Indies and focus particularly on the atrocities committed by the colonizers against the indigenous peoples. So he just felt the need to do it.
Becuase they knew what they were doing
