The evidence that is relevant to Kennedy's claim that the United States is falling behind the Soviet Union is:
We are failing to develop the natural resources of the United States to the fullest.
The Soviet Union by 1975 will be producing more power than we are.
While the other two points he mentions are also relevant to the strength of the United States as a society, they do not directly support his claim that the Soviet Union is surpassing the United States in certain areas.