Complex sentence: In astrophysics, electric field screening is important because it makes electric fields largely irrelevant, but because the fluids involved have charged particles, they can generate and are affected by magnetism which is a very relevant and complex area of astrophysics.
Split into simpler sentences: In astrophysics, electric field screening is important because it makes electric fields largely irrelevant. However, because the fluids involved have charged particles, they can generate and are affected by magnetism which is a very relevant and complex area of astrophysics.