A-levels for Marine Biology?

I am private tutor - I teach maths/stats, physics, chem and a few other subjects - I have a student who has just done his GCSE's - (maths-disappointing B, phys-B, chem-B, geog-B, eng-B+B) he's gravitating towards Marine Biology as a degree subject - maybe the Aber course on Marine & Freshwater Biology where they currently require a B in Biol (or a C in Biol plus another C in a Science subject) - for people on the course what A-levels did you decide to take? He really wants some guidance on deciding whether to take maths or geog through to A2. I can see him getting B or C's for any of his A-level subjects - possibly a C rather than a B for maths, maybe a B or even a C for chem - no idea about biol and geog atm.

The subjects he likes best are biol & geog, then chem and then maths and physics - he's definitely settled on doing biol & chem at A-level but not sure which 2 other subjects to take and which 1 to take through to A2 - he'd prefer geog to maths (or physics), but I wondered if maths might help him more on a marine biol course - geog seems a better choice to me but I am just starting to look into it.
TIA

Neil