An infection may be intracellular or extracellular, depending on this?
bacteria
pollen
microbes
pathogen
22.3 Magnetic Fields and Magnetic Field Lines • Magnetic fields can be pictorially represented by magnetic field lines, the properties of which are as follows: 1. The field is tangent to the magnetic field line. Field strength is proportional to the line density. Field lines cannot cross. Field lines are continuous loops.