Question

define trough and crest.

Answer 1

Crest = The maximum positive displacement on a sound wave is called crest.
Trough = The maximum negative displacement on a sound wave is called trough.

Answer 2

the vertebrates anatomy .. the throat is a front part of neck.. position in a front of a vertebra . lt contain a pharynx and larynx . an important section of it epiglottis .. which is flab separating the esophagus from the trachea windpipe preventing food and drink being inhaled into the lunges