If that Martian looked at battlefields, they would find that people had only muskets at the time of the Civil War and that they had repeating rifles at the time of the Spanish-American War, and then they had machine guns by the time of World War I.
Se aquele marciano olhasse  os campos de batalha, saberia que as pessoas só tinham mosquetes no tempo da Guerra Civil e que eles tinham rifles no tempo da Guerra Hispano-Americana, e que então eles possuíam metralhadoras na época da Primeira Guerra Mundial.