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Answer: High Frequency waves by method of compression bone conduction
Explanation: in this, vibration of the bones of the skull and sometimes, arguably soft tissues leads to the production of sounds. The outer and middle ear is bypassed in this method of sound production. Sound reaches the inner ear directly and its a process largely involved in designing hearing aids.
The brief description of the project is called Abstract.
Option B.
<h3><u>Explanation:</u></h3>
An abstract is defined as a brief description of the project or content of an article, speech, or a book. An abstract is given at the beginning of the book or project to describe what's the topic of the project, what the project is going to prove, or to explain.
An introduction on the other hand is a description about the project topic, the prevailing idea, or explaining the topic of project.
A reference is described as the source from where the data of the project are collected or hints are taken.
A summary is the paragraph briefly describing the project conclusion at the end of the project, to briefly explain everything about the project.