The correct answer is option 1: Wavelength.
Wavelength refers to the distance between two successive crests or troughs of sea waves. It can be measured as the distance from one crest to the next or from one trough to the next.
Option 2, wave height, refers to the vertical distance between the crest and the trough of a wave. It is a different measurement than wavelength and does not represent the distance between crests or troughs.
Option 3, wave frequency, refers to the number of waves passing a certain point in a given time. It is measured in cycles per second or Hertz (Hz), and it is not directly related to the distance between crests or troughs.
Option 4, fetch, refers to the distance over which wind blows in a specific direction. It is not directly related to the distance between crests or troughs of sea waves.
Overall, the correct term for the distance between two successive crests or troughs of sea waves is wavelength.