Hi Lulu,

I'm not familiar with the IGCSE standards, so I cannot provide much information about those, but I'm happy to tell you more about our NGSS science courses.

The NGSS courses are based on the Next Generation Science Standards and we have courses for both Middle and High School students. At this point, the high school NGSS courses are designed to supplement NGSS classrooms, but they are not meant to be used as standalone courses.

If you're wanting to use Khan Academy's courses to study on your own, then I suggest using the regular High School Biology and High School Physics courses instead. These can be used as standalone courses, so they will be more in-depth than the NGSS courses.

I hope this helps! Please let me know if you have any further questions!