What is population at risk and indicate which of the elementary students are not at risk.

Twenty-five children in Fallsburg Elementary School (with a population of 60 pupils) received their immunization against whooping cough to protect the school’s student population. In your role as health officer, you collected the documentation from parents on the first day of school. You found that 25 students had received their immunization against the disease. You have been asked to explain some basic epidemiologic concepts to the parents who did not have their children immunized.
You have been tasked to do the following:
Define the term population at risk and indicate which of the elementary students are not at risk.
Also describe the difference between incidence and prevalence.
Be sure to justify your response with evidence from the literature.
Length: 2–3 pages, excluding title page and references.
Assignment Expectations
Assessment and Grading: Your paper will be assessed based on the performance assessment rubric that is linked within the course. Review it before you begin working on the assignment.
Your work should also follow these Assignment Expectations.