The House of Burgesses became a representative assembly because it had representatives from all boroughs or cities of Virginia.
This general assembly functioned as a parliament and passed several laws for the entire colony of Virginia.
EXPLANATION:
The House of Burgesses also worked as a local government body for the different cities or boroughs of Virginia.
The assembly also had elected members; two each from the ten settlements of Virginia thereby allowing every part of Virginia to be represented in the parliament.