It depends on whether there are a lot of people doing biology, it also depends on how good your school is academically as a more stricter school would most likely not allow it. It also depends on how high or low the grade 4 is.
And last but not least, it depends on your maths teachers opinion of you, they could easily convince the people in charge that you're hard working or lazy. So if your teacher likes you (as a student ofc) and you're a fairly off a 5 get them to stand up for you, this also applies for whether you miss science by one grade.