Areas of the body affected by trapped gas expansion from a change in pressure include:

Trapped gas expansion due to changes in pressure primarily affects areas of the body that contain air-filled spaces. The correct selection highlights key areas where gas expansion can lead to discomfort or barotrauma during scenarios such as changes in altitude.

The ears are particularly vulnerable due to the Eustachian tube's need to equalize pressure; if this does not happen smoothly, discomfort and potential damage can occur. Teeth can also be at risk because they may contain trapped gas in cavities, leading to pain as atmospheric pressure changes. The sinuses are similarly affected; they can experience pressure changes, resulting in sinus pain or discomfort. The gut is included as well, as it contains air pockets that can expand and cause bloating or pain during rapid ascents or descents.

In contrast, other selections may contain regions that are less impacted by trapped gas expansion or include areas that don't directly relate to the changes in ambient pressure in the same way. For example, while blood can have issues related to pressure changes (such as decompression sickness), it does not experience gas trapping in the same manner as the air-filled spaces highlighted in the correct choice. Thus, the focus on ears, teeth, sinuses, and gut makes for a comprehensive understanding of the effects of