In a world where everyone has transparent skin, making their internal organs visible to onlookers, Priyanka stands behind a large, opaque structure and cannot be seen directly by her friend Aarav who is standing on the opposite side. If Priyanka steps out from behind the structure, but in such a way that only her back is visible to Aarav, what will Aarav be able to discern about Priyanka's emotions? Provide a short response.
Given that everyone in this world has transparent skin, under normal circumstances, Aarav could potentially observe Priyanka's internal reactions as visible indicators of her emotions, such as her heart rate or blushing of internal tissues. However, since Priyanka is only showing her back to Aarav, he would not be able to see her facial expressions or any changes in the front part of her body that could signify her emotional state, such as her heartbeat or stomach movements, assuming these are indicators of emotion.

Yet, because Aarav can see through Priyanka's transparent skin, he might be able to observe the movements of her back muscles, the tension in her spine, or the rate at which her lungs are expanding and contracting, which may provide some clues to her emotional state. If Priyanka is feeling scared or anxious, her back muscles could be tense and her breathing may be quick and shallow. If she is feeling calm and relaxed, her muscles might appear relaxed and her breathing slow and steady.

Therefore, while Aarav cannot directly observe Priyanka's facial expressions or frontal indicators, he can infer her emotions to some extent by interpreting the observable physiological changes in her back muscles and breathing patterns.