Built-in Functions

Which of the following functions will not result in an error when no arguments are passed to it?
What will be the output of the following code?
Print(len(['hii',0, 2, 4]))
What will be displayed by print(ord(‘a’) – ord(‘b’)) ?
What will be displayed by 'helloworld'.replace('l', 'e')?
What will be displayed by min(max(False,-2,-6), 3,5,6) ?