Explanation :
In transverse waves the particles are oscillating perpendicular to the direction of propagation of waves.
The uppermost part of the wave is crests and the lowermost part is troughs.
Wavelength of a transverse wave is defined as the distance between two consecutive crests or troughs.
Amplitude is the maximum distance or displacement covered by a wave.
So, crest, amplitude, trough and wavelength identifies the parts of a transverse wave.