question: The behavior of which two phenomena caused physicists to encounter problems with their understanding of time in the late 19th century ?
answer: the behavior of electricity and magnetism
turker_answer: The behavior of electricity and magnetism caused physicists to encounter problems with their understanding of time in the late 19th century .
rule-based: The behavior of the behavior of electricity and magnetism two phenomena caused physicists to encounter problems with their understanding of time in the late 19th century .