please help, im stuck!

Introduction In a local park, a crime has been committed; however, there is evidence that the current location in the park is not the original crime scene. Park is several hundreds acres and would take hours to search. But this park is unique that there are some very distinct areas in the park that contain only certain types of plants. It was noted that there appeared to be some pollen on the clothes and that this could narrow down the potential area for the original crime scene. Your job is to identify the pollen on the clothes and determine which strain of plant it belongs to and therefore the area in the park to search. Please use the hints provided as they are designed to help you with answering the questions. Good luckt. If the Hibiscus pollen in the image appears to be 4.8cm what is the actual size of the pollen in micrometers