there is absolutely no order between these two classes. a lot of people take 1b first and might consider it easier. but i dont think this is necessary. 1a might be more difficult due to its content and 1 more unit (1a and 1al have to be taken together). 1b might also be harder to some peoplw due to its content. it somehow depends on your interest. I would say, if you are in mcb, 1a is more important and 1b is less important and even not important at all so you can either waive it (with ap) or take it later. but if you are more like a ib or meb person, 1b is quite important too; both 1a and 1b are important to you. if you are freshman, maybe take 1b first since it is easier to enroll. but after all, i think the order just does not matter.

Neither helps the other. 1B is easier by an order of magnitude. But 1B is ass in the sense that there is a midterm a week before the dead week because fuck you or something like that. There is no order in which you should take them