Final answer:
The Bod Pod machine uses air displacement to determine body density as part of body composition assessment.
Step-by-step explanation:
To meet body composition measures, the Bod Pod machine determines body density by measuring the amount of air displaced. Unlike the other options listed, the Bod Pod uses air displacement plethysmography to accurately assess body composition. In contrast, DEXA (Dual-energy X-ray absorptiometry) measures bone density and fat content using low-dose X-ray beams, and an MRI (Magnetic Resonance Imaging) uses magnetic fields and radio waves to image organs and structures inside the body. Ultrasound assessment in body composition is less common and uses high-frequency sound waves to visualize tissues.