Hello!
I'm not 100% sure, as I'm only a first year, but i'll try my best anyway. I just looked at the unit ECON111 course (for example), which is offered in different streams. From what it says: The lectures are organised into three streams. Each stream covers the same material although the
lectures may differ. The lecture streams are not interchangeable. It is imperative that you do not
switch between lecture streams. Although the same content is covered in each stream, the
lecturers may cover the material at a different pace, and in a slightly different way, in each stream.
Hence you need to attend one stream.
This is for this course. But hopefully you can get an insight of what your course may be designed in terms of streams. But please don't rely on me. I recommend you really ask them to get the right information! But I hope I helped somehow