A police officer is at a crime scene and locates a footprint in a flowerbed near an open window. The window is examined closely and pry marks are discovered on the lower window sash and the window sill indicating forced entry. The police officer pointed out the evidence to the investigator who photographed the evidence and collected the footwear impression using a liquid footwear casting system. Who is required to testify in court to get the evidence admitted during the trial?

Danilo has been working for metropolitan taxi for three months. he expected that his job would be to drive around the city, pick up fares, and drop them off at their desired locations, but in his first few days on the job he realized that the job entails much more. he must keep his taxi cab clean and neat, and some days he will be stationed at the shop and go to people's houses to pick them up and bring them to the local airport. within a few months, he has learned that taxi drivers often express frustration with the people they call "civilians"—that is, non–taxi drivers, whose driving skills they complain about incessantly. in his first few months on the job, describes what danilo is undergoing.