The two main parts of a wave are the a. swell and whitecap. c. crest and trough. b. wavelength and wave height. d. rise and dip.

Answer : The two main part of a wave are crest and the trough.

Explanation :

A disturbance in a medium is called a wave. There are some important part of a wave. For example, crest, trough, amplitude etc.

The maximum displacement of a particle is called the amplitude of the wave.

The crest of a wave is defined as the topmost part of a wave while the trough is the lowermost part of the wave (as shown in figure).

Hence, the correct option is (c) " crest and trough ".

the bal will not change its velocity.