Let me address a couple of them.
"Blowin'in the Wind" is a song dealing wioth a more general feeling of powerlessness. Though you have often heard it as a nice little song asking a few questions, try reading the lyrics in an accusatory and angry tone. Its far more than a lament. Its an angry plea. Bob Dylan wrote many songs open to interpretation by mood, but the questions ask in this one were the angry cries of young people at the time.......and many of us felt powerless and angry at the actions of our government.
"Where Have All the Flowers Gone" speaks to the waste of war, but also to the things lost as we mature. We lost many fine people to the VietNam war on the field of battle, but we lost more in the aftermath of that war. A large segment of the youth of the day were affected for life by the times in which they came of age.
"Ohio" was written after Davd Crosby gave the article on Kent State to Neil Young. They say Neil went off for a few hours and came back with this song. More than the lyric, the hard driving arrangement done by Stills added to impact. It expresses that same anger for senseless loss so often seen in period songs.
There are a lot of other songs fromthe period that speak even more to the point, but I assume you were assigned these. We ran a thread on "Songs of the VietNam War" that you and your teacher may also find interesting.
Probably most important to remember is that these songs were written and sung by people only a few years older than you are now. We were asked to make decisions that young people should never have to make. One day we were at the prom and the next were in VietNam or jail. It was a turbulent time.