Answer 1

Python 2.#
print a

Python 3.#
print (a)

Answer 2

python 2 vs python 3

sololearn uses python 3

Answer 3

print as a statement is one of Guido's 'Python Regrets' and was fixed to be a function in 3.x.

One gotcha: tuples are surrounded by (). Make sure you know the context of the code you're reading.

Answer 4

You can still see such primitive printing in Ruby, supposedly one of the descendant languages of Python