Answer:
Jenn has achieved an understanding of gender constancy that Sadid has not. Gender constancy is the understanding that one's gender remains the same regardless of external appearances or behaviors. In this scenario, Jenn laughs because she understands that putting a barrette in Sadid's hair does not change his gender identity. She recognizes that gender identity is an inherent aspect of a person's identity and is not determined by superficial actions or appearances. Sadid, on the other hand, expresses distress because he does not yet have a fully developed understanding of gender constancy and may associate certain behaviors or appearances with specific gender roles or stereotypes.