Does calling many methods adds to the overhead of the program python

Which of the following is a way the operating system prevents unknown or unauthorized users from accessing the system?

Hassan is writing his master’s thesis, which is a thirty-page document. he received some feedback from his professor in the form of comments, but does not see where the comments are. what is the fastest way for hassan to find the feedback?

Which type of file can be used to import data into a spreadsheet?