You Should Always Keep a Copy of a Professional Letter

question 21

True/False

You should always keep a copy of a professional letter you send out.

---

Definitions:

Sound Properties

Characteristics of sound waves, including amplitude, frequency, and timbre, that determine the perception of sound.

Medium

A channel or means for the transmission of information or data, or a substance in which something else is conveyed or occurs.

Vibration

An oscillation or rapid motion back and forth or up and down of particles in a medium or an object.

Molecules

The smallest unit of a chemical substance that can exist independently while retaining the composition and chemical properties of the substance.