Which service is least likely to require a chemical analysis?

When considering the services listed, beard trimming is least likely to require a chemical analysis. Chemical analyses are typically conducted for services that involve altering the structure or color of hair, such as hair coloring, chemical straightening, and chemical perming. These processes use various chemicals that can react with the hair, necessitating a thorough understanding of the hair's condition and what specific chemicals are involved to avoid damage and ensure effective results.

In contrast, beard trimming generally involves cutting hair with scissors or clippers, without the use of chemicals. As such, it does not require an analysis of chemical interactions, making it the simplest and least complex of the options provided. Beard trimming focuses on aesthetics and maintenance rather than chemical processes that affect hair structure.