Biology is really broad so you will definitely be keeping your options open by taking it and have a range of career paths you could follow. Id strongly recommend it if you enjoy the subject! Here’s a link on the types of jobs people tend to go into with a biology-type degree:
https://www.prospects.ac.uk/careers-advice/what-can-i-do-with-my-degree/biologyBiology and Maths is quite common to take together for a range of fields: healthcare, zoology, ecology, microbiology etc. Doing Biology and another core science (chem, physics, maths) would keep your options wide open for a massive range of life science courses, if you enjoy biology youre likely to find something you’d love to study from this kind of combination!
Try looking through some of the degree guides on sites like uniguide or unifrog because they can help you figure out what kind of thing you like but honestly if you have no idea thats absolutely fine! The best thing you can do is to take subjects you enjoy and see where they take you, lots of people start sixth form with a specific idea in mind and then change it because they find they enjoyed a particular subject a lot more than they expected. Also dont think too much about the money, healthcare isnt really high paying even, money doesnt buy happiness and i dont know about you but id rather have a job that i love!
So from maths, fm, biology, chem, econ and geography… I would recommend you do biology as youve said you enjoy that and maths is good to keep your options open across all the areas you’ve spoken about. Here’s what id suggest:
If youre interested in Physics/engineering type degrees- physics and maybe fm
If youre interested in economics/finance type degrees- fm and maybe econ
If youre interested in lab type science- chem
If youre interested in the environment- chem would be useful and geography interesting but not essential