The process of converting a continuous signal to a series of 1s and 0s introduces small errors to the sound as it is recorded. what is this process called?

Quantization

Quantization maps input values from continuous data into digital signals. This process is common in signal processing of sound, wave and seismic signals.

Round off and truncation errors are common in truncation processes.
Truncation errors are easier to control, but round off errors are dictated by the data processing hardware.

No because a circle or pie graph usually shows percentages you'd need a line graph