Answer: D) women's colleges
Explanation: The reform to the American education system that began in the early nineteenth century was women's colleges. Around this time, more educational opportunities for women began to emerge with the founding of the first colleges that women could also attend.
they were getting severely hurt.
It’s C most trading was done either on land or over sea
An Invisible Warfare is basically when the victims of an attack are unaware and without warning nor immediate knowledge are being attacked.