Answer 1

Quote from website:
To come back to our initial question what is used in Python: The authors who call the mechanism call-by-value and those who call it call-by-reference are stretching the definitions until they fit.
Correctly speaking, Python uses a mechanism, which is known as "Call-by-Object", sometimes also called "Call by Object Reference" or "Call by Sharing".

Source: https://www.python-course.eu/passing_arguments.php

C does by value and by reference:
http://cs-fundamentals.com/tech-interview/c/difference-between-call-by-value-and-call-by-reference-in-c.php