Web development frameworks take the concepts we've been working with and provide a higher level of abstraction to work at; reducing the amount of ad hoc and boilerplate code. This reduces effort, but more importantly reduces the opportunities to introduce bugs. Frameworks provide more or less guidance (refered to as opinionated) to the developer, to promote best practices and already tested code.
In this assignment, your team of 3 will explore a web development framework and present it to the class. What we want to hear about is:
Every framework is different, but they either use an MVC model or notably do not, so talk about it in those terms. Some lightwight frameworks (Slim, Flask) don't include all things "in the box". In that case, you have to find the communities' generally accepted add-ons (e.g. SQLAlchemy for ORM in the case of Flask).
You can choose other ones, just run it by me. These are just major ones I'm aware of. You do have to do something 3-tier, not direct connect from client JS to the DB (e.g. couchdb).