Question

scientists use the theory of plate tectonics to understand the reasons volcanoes develop in certain locations. how does this show the validity of the theory?
the scientists are repeating the experiments.
the scientists are making predictions.
the scientists can see the plates moving beneath the volcano.
the scientists are using observations.

Explanation:

The theory of plate tectonics allows scientists to predict where volcanoes will form based on the movement of tectonic plates. Predictive - power is a key aspect of a valid scientific theory. Repeating experiments isn't relevant here as it's about using a theory for prediction. Seeing plates moving beneath a volcano is not the main way this shows the theory's validity. Using observations alone doesn't fully capture the predictive nature of the theory's application.

Answer:

The scientists are making predictions.