Explanation:
Therefore, the strategy that is NOT an effective measure for preventing the spread of illness is separating the children by age group
This question asks about effective strategies to prevent the spread of illness. It mentions several strategies including health checks, hygiene practices, segregating children by age, and sanitization. Effective prevention strategies for the spread of illness include regular health checks to identify if a person is carrying a disease, practicing proper handwashing and hygiene to reduce the chance of transmitting germs, and sanitizing materials and equipment which remove germs that could cause disease. However, separating children by age groups does not stop the spread of illness. There is no guarantee that communicating with the same age group could help them distance from illness since disease-causing germs and viruses can infect anyone regardless of age. The virus transmission happens due to close contact with an infected person or touching an infected surface, not because of the differences in age groups.