The two sources disagree on the effectiveness of recycling programs in schools.
Source 1 emphasizes that participation is necessary for recycling programs to have a positive impact on the environment, suggesting that schools can successfully contribute to recycling efforts.
Source 2, on the other hand, suggests that getting all students to follow a specific recycling program can be challenging, which implies that such programs may not be effective.
Therefore, the answer is:
"Successful recycling programs require the participation of many people."