Answer 1

It can't work because input() wasn't stored in a variable.
Try this:-

input=input()
print(input)

Or just a one liner:-

print(input())

Answer 2

we should not use names of built-in functions as variable names, as the following code demonstrates:

input=input()
print(input)
name = input()

the program crashes at the 3rd line.

Answer 3

in 'print(input)' after input you have not put () brackets so it is not a function but a reserved keyword so no error but it prints about it.