Why does a democratic country need a constitution?

Any democratic country needs a constitution because of the following reasons: a) Constitution lays down rules that guard against the misuse of power by our political leaders.

b) The constitution of country guarantees right to equality to all the citizens of the country.

c) There are also some fundamental rights and duties that the constitution provides to its citizens.

d) It also ensures that a dominant group does not use its power against other less powerful people or groups.