In the extract from the book "4 hours" in "My Lai" by Michael Bilton, what does he tell us about the American Army in Vietnam?

Source A tells us of the problems faced by America during the Vietnam War. It says that troops were drafted into the US army and scored so low on the IQ tests that they should have been rejected from service.
We are told that the army being sent to Vietnam was on a tour of duty of about 1 year and had an average life expectancy of 6 months, which meant that, as the source puts it, "a rookie army was constantly throwing inexperienced men against experienced guerrillas on their home ground." The evidence for this is that in one week of war 552 Americans were killed.
There is evidence for his…