By law, you have to do science, maths, english and PE... and I'm not sure whether you have to do ICT... the rest depends on your school. My school made it compulsory to do one humanities subject and at some schools you have to do a language.
It depends on the option boxes. The subjects will be laid out in boxes and you choose one subject from each box. Generally geography and history will be in different boxes because they go well together. Your school should arrange it so that you can take complementary subjects together.
If you go to a religious school RE is also compulosry. And you don't get a qualification for compulsory PE - it's just to keep you active. ICT is also compulsory at some schools.