Question

volume or intensity of a sound wave is measured by the size of the ______ and reported in decibels.
a amplitude
b frequency
c trough
d wavelength

Explanation:

Sound wave intensity (volume) relates to the wave's maximum displacement from its resting position, which is amplitude. Frequency affects pitch, trough is a low point of the wave, and wavelength relates to frequency and wave speed, not volume/intensity. Decibels quantify this amplitude-based intensity.

Answer:

A. amplitude