Final answer:
To achieve a normal body composition, the student should aim for a BMI within the normal weight range of 18-24.9 by implementing a healthy diet, regular exercise, and seeking professional guidance if needed.
Step-by-step explanation:
The student in question has a BMI of 28, which falls within the 'overweight' category. To achieve a normal body composition by summer, a good benchmark for this student would be to aim for a BMI within the normal weight range, which is between 18 and 24.9. This would involve implementing a healthy diet, regular exercise, and possibly seeking guidance from a healthcare professional or nutritionist to create a personalized plan.