Final answer:
When human resources contribute to a firm by creating high value and differentiating it from its competition, it represents a core competency of the firm.
Step-by-step explanation:
When the human resources function creates a unique capability in a firm that creates high value and differentiates the organization from its competition, human resources is a core competency for the firm. This is because a core competency is something that a company does particularly well compared to its competitors, providing a unique advantage. The development of human capital through the acquisition of skills, knowledge, education, and overall wellbeing contributes significantly to the firm's productivity and innovation. This investment in workers translates directly to the firm's capacity to offer unique value, thereby being a core competency.