Final answer:
Without specific data about the distances between points L, M, N, and P, it's not possible to determine which distance measures 7 units. The references provided discuss units of measurement and conversions, not the actual distances between the points in question.
Step-by-step explanation:
The student's question is asking to identify which distance measures 7 units based on the information provided. To determine this, we would need specific data about the distances between points L, M, N, and P. However, none of the provided references give us direct information about these points and their distances. Without such information, it's not possible to accurately say which distance measures 7 units. The provided references discuss units of measurement and conversions between them, but they do not provide the actual distances between the points in question.
For example, one could convert and compare measurements given in meters and millimeters as in the prompt stating to convert 7 m to 7000 mm, but this does not answer the student's question about the specific distances between points.