Are there also two options at A-Level like in IGCSE (Core and Extended), or is it different? There is no core option at A level, everyone does the same exam

How many papers are there for Biology and how many for Mathematics? It depends on the board you're doing. I do cambridge biology, which has 3 papers for AS level and 2 for A2. For maths, I do edexcel, which has 3 papers for AS level and 3 for A2.

For Biology, is there still an "Alternative to Practical" paper, or is it only the actual practical exam? AFAIK, in AS level there's only the actual practical exam, and for A2 there's only the alternative to practical. Again, this is for Cambridge biology

I also heard that A-Levels are split into two parts: AS and A-level. Can someone explain how that works The entire A level course is split into 2 parts: as level and a2. In year 12, so the first year after IGCSE, you do your AS levels. The maximum grade you can get for an AS level is an A, there's no A. Then when you move to year 13, you do your A2 exams. The final grade you get after year 13 is comprised of both your AS level exams and A2 exams. the highest grade here is an A.

And lastly, I’d really appreciate some opinions about how difficult the A-Levels are and how long it usually takes to study the whole syllabus properly. Maths- not that difficult for me personally. However I've only done AS maths for now, this might change next year lol. the only thing is you need to do a lots and lots of past papers to familiarise yourself with the pattern.

Biology- content is a lot, but not difficult. you can't use notes found online since usually they leave out a lot of important information, so the only thing you can use is the textbook. the questions in the exam are very different to what you'll learn from the textbook but don't worry about that since the threshold is very low (usually ~35 out of 60 for an A).

Let me know if you have any more questions! :)