Answer:
They had begun to question the cost of the Vietnam War.
Explanation:
By 1969, opposition to war had rose. American cities were the scenarios of mass rallies and marches for peace and a withdrawal from Vietnam. The public was worried about the high number of casualties and the economic costs of the war.
They did not see the purpose of fighting and were increasingly distrustful of the official version told by civilian and military officials, especially after the images of North Vietnam´s Tet Offensive of 1968 revealed chaos and uncertain perspectives of victory.
There was no rain for a long time so the Mayan cities disappeared
