What was a sign that a dinasty had lost the mandate of heaven a. invasion by nomadic warriors. b.election of a new dynasty. c.an increase in the imperor's political authority .d. the start of a new religious movement

A. Invasion by Nomadic warriors.

Explanation: The Mandate of Heaven was a doctrine use to justify an Emperors rule. According to beliefs, Heaven, imposed the doctrine on a just ruler. But if there were to be droughts, plagues or if the ruler would be overthrown; it was viewed as heaven being displeased with the emperor and the mandate had been withdrawn. In this case, an invasion can be seen as a sign of punishment.

the space race was a battle to make advanced technology to get to the moon and to get a better understanding of space.