Tip #3: Variable names are case sensitive.
In python we can declare two variables with names animals as well as Animals. Python will consider these as two different variables, as their case differs. i.e a is capitalized in the second variable.
We can also declare ANIMALS, ANiMaLs, AnIMalS and Python will still recognise these as valid variables. However it is not considered a good practice to have similar variable names in Python.