Final answer:
The governess is confused by Mrs. Grose's response because it reflects the societal norms and personal values related to aesthetics influencing employment in their era.
Step-by-step explanation:
The governess's confusion stems from the socio-cultural norms of the time regarding beauty and hiring practices of domestic helpers. When the governess comments on the uncle preferring young and pretty individuals, it reflects societal attitudes towards aesthetics and personal appeal influencing employment.
Mrs. Grose's response likely indicates surprise or discomfort, as she may sense an underlying implication about the uncle's character or the superficial criteria used for hiring, which could be inappropriate or unprofessional. The governess's observation and the subsequent reaction reveal the complexity of social dynamics and personal values of that era.