Which of the following statements about nodes is true?

Nodes are points in a wave where the wave function is zero, meaning there is no displacement of the medium at those locations. This is particularly evident in standing waves, where certain points remain stationary and experience no movement due to the constructive and destructive interference of two waves traveling in opposite directions.

Understanding that nodes correspond to locations of zero amplitude reinforces the idea that they are critical in the formation of standing waves. In these waves, nodes are spaced at intervals along the length of the medium, and they represent the points where the wave's energy is effectively "cancelled out."

The other statements in the question do not accurately represent the characteristics of nodes. For instance, nodes are not locations of maximum wave energy; rather, these points indicate minimal energy. While nodes do exist prominently in standing waves, they can also be observed in other wave phenomena involving interference. Furthermore, nodes influence the overall wave function since they indicate places of zero amplitude and play a crucial role in determining the properties of the wave.

Thus, the selection of the statement regarding nodes marking the zero line on a wave accurately captures their essential nature and role in wave behavior.