Most colleges have GE requirements beside your major requirements. UCSD just has different GE requirements based on the residential college you select. If you just want to study Biology, then going to college in the US may not be for you not just UCSD. What other colleges/universities did you apply?
If you use the link I posted above, you can compare the GE requirements for each UCSD college to get an idea of what type of courses you need to take.
Here is a link to an explanation of the colleges regarding dining, location etc… by a CC poster:
Here is a four year plan for a Biology major. You pick the specific college at UCSD.
You are usually given options of which GE courses you need to take so there is some flexibility unless you have a required course that has be taken by all students in that particular college.