Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: CRITICAL THINKING QUESTIONS 19. How are neurons similar to other cells? How are they unique? 20. Multiple sclerosis causes demyelination of axons in the brain and spinal cord. Why is this problematic?. Answer: infinite
Output:
The existence of (virtual) photons is possible only by virtue of the heisenberg uncertainty principle and can travel an unlimited distance, so the range ofthe electromagnetic for is what?