Final answer:
The positive effects of service learning are less likely to occur when the service is disconnected from the curriculum, whereas involvement in meaningful, reflective, and community-collaborative services promotes positive outcomes.
Step-by-step explanation:
The positive effects of service learning are most likely to occur in all of the following circumstances, except when: a. The service is disconnected from the curriculum. Service learning should ideally be connected to academic content to ensure it enhances the educational experience and resonates with students academically. Circumstances that promote positive effects include: b. Reflection being a key component of the service, as this facilitates a deeper understanding and personal growth; c. The service being meaningful and relevant to students, which increases engagement and the likelihood of a positive impact; and d. The service involving collaboration with the community, as this fosters a sense of partnership and empowerment among those involved.