String Quartets

I am doing a music paper for my IB diploma, and I think I will do it on the subject of String Quartets. Now my topic wouldn't be this broad, but it would have something to do with them.

So I ask you,

Why do you think String Quartets are so popular?

Why do composers write for them?

What makes it a unique/versatile ensemble?

What makes it a good ensemble?

What are the pros and cons of the String Quartet?

I just want to know everyone's thoughts on the subject. The questions are just some I thought off the top of my head, feel free to add whatever you want.

Thanks.

In other words.... you want us to write your paper for you :P

That would be very nice, any takers?

Seriously, I just want to hear different opinions to help me get started (it's kind of a big subject).

Also, it would also be interesting to hear what people think.

Well, the four insturments in the string quartet blends very nicely together, compared to other ensembles like woodwinds ar brasses. It is useful because string quartets cover a broad range, and they are capable of playing many kinds of articulations like tremolo, vibrato, pizzicato, arco etc. etc.Their volumes are also similar to each other so they won't dominate an entire piece of music.

In other words, they are one of the easiest ensembles to write for. Well, that's all I can think of now.