Final answer:
Claustrophobia and excess abdominal fat might be barriers to body composition assessment via air displacement, but being submerged in water, severe thinness, and asthma are not related to air displacement methods.
Step-by-step explanation:
The question asks what might be a barrier to having body composition assessed via air displacement. The potential barriers could include claustrophobia, as the assessment involves being enclosed in a small chamber, and excess abdominal fat, which might affect the measurement process.
However, fear of being submerged in water, severe thinness, and asthma are not related to air displacement body composition assessments but are rather potential barriers for hydrostatic weighing, where the subject is submerged in water.