The correct answer for 1 is destroyed weapons
There were huge pyres built where weapons would be destroyed or if they were completely metal they would be melted. It was a sign of good will by individual countries to show that they don't want to militarize even more and that their armament days are over. All league of nations members supported this idea and didn't want to wage more wars.
The correct answer for 2 is cooperation
The idea behind the league of nations was to make an organization like the one that the United Nations are nowadays, numerous countries working together to prevent wars and destruction. The idea failed however since the United States didn't want to support it and people used this to attack weak European countries.
The correct answer for 3 is that he stated his support for an isolationist policy
He believed, like most Americans at the time, that the United States should not meddle in European affairs and that participation in world war one was unnecessary. When Harding left the League of Nations, the League started losing power and eventually it became pointless since wars kept happening without them.