Explanation:

Independent judiciary is essential for a democracy, whether direct or indirect. Universal Adult Franchise is the right to vote based only on the criteria of age. This too is essential to enable people to elect their government. But Referendum is a method where people directly vote to validate or invalidate a law, usually practised in Direct Democracies, e.g Brexit. Since India is an Indirect Democracy where laws are made by people's representatives and not by the people themselves, Referendum is not a feature of representative democracy.