Drag and drop each description into the correct category They copy the original sound
Analog signals
Digital signals
They change sound into numbers.
They reduce unwanted noise.
They may pick up unwanted noise.
They flow continuously.
They do not flow continuously
Intro
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Explanation:

Analog signals :

Analog signals are continuous signal. These are like wave signals that change with time period.The main disadvantage of analog signal is that it contains noise. .They flow continuously.

Digital signals :

Digital signals do not flow continuously. It has finite number of values. They form in the form of numbers. They reduce unwanted noise. It is the advantage of digital signals.

The rocks expand when there hot/warm  and contract when they are cold.