Final answer:
Gender constancy is the understanding that one's gender remains the same across different contexts and circumstances. Preschoolers' willingness to cross gender lines in their behavior may be influenced by their understanding of gender constancy.
Step-by-step explanation:
Gender constancy is the understanding that one's gender remains the same across different contexts and circumstances. It is the recognition that one's gender is a stable and inherent part of their identity. Preschoolers may be (un)willing to cross gender lines in their behavior due to their developing sense of gender constancy. When preschoolers have a strong understanding of their own gender identity, they may be more likely to adhere to the expectations and stereotypes associated with that gender, leading to a reluctance to engage in behaviors that are perceived as crossing gender lines.