Retard
Decrease
Wave
Flood
Answer is Right!
Answer is Wrong!
The correct answer is C. Wave.
An undulation is a wave-like movement or form. It can be caused by a number of things, such as wind, water, or sound. Undulations can be seen in many different things, such as the surface of a pond, the hair on a person’s head, or the sound waves produced by a musical instrument.
The other options are not synonyms of undulate. Retard means to slow down or delay something. Decrease means
to make something smaller or less in amount. Flood means to cover an area with water.