Final answer:
Megan may have asked Jessie for an index card because she needed it for a specific purpose related to 4th grade.
Step-by-step explanation:
In this scenario, Megan asked Jessie for an index card after expressing her worry about going to 4th grade because she may have needed it for a specific purpose related to the upcoming grade. The exact reason cannot be determined based on the given information, but asking for an index card could be associated with a need to write down important information, make study notes, or complete an assignment. It's important to consider that the specific context and details of Megan's situation would provide a clearer understanding of her reasons for asking for an index card.