Following is a list of meaningful subject combinations at second and third year level in a BSc degree:

• Biochemistry: Chemistry, Microbiology, Botany, Computer Science or Zoology.

• Botany: Chemistry, Microbiology or Zoology.

• Chemistry: Biochemistry, Geology, Mathematics, Microbiology, Physics, Zoology.

• Geology: Chemistry, Physics, GIS, Computer Science, Soil Science, Geography.

• Geographic Information Systems (GIS): Botany, Computer Science, Geography,Geology, Physics, Statistics, Zoology.

• Geography: Botany, GIS, Geology, Computer Science, Zoology, Chemistry.

• Microbiology: Biochemistry, Botany, Chemistry.

• Zoology: Biochemistry, Botany, Geography, Geology, GIS, Microbiology

You can find your combination of interest according to the career you want to opt for. I hope this helps you.
All the best!