Passage Summary: When astronauts float in space, their eyes see them moving but their ears don't feel it, and this sensory disagreement is the suspected cause of their nausea.

Conclusion: Motion sickness is likely caused by the brain receiving contradictory sensory data regarding the body's movement.

Reasoning: In weightless environments, astronauts' eyes observe movement relative to their surroundings, yet their inner ears report no physical movement, and these astronauts frequently suffer from motion sickness.

Analysis: To strengthen this hypothesis, we need to find evidence that reinforces the causal link between sensory conflict and sickness. Look for an answer that shows this phenomenon occurring in other contexts or demonstrates that when the conflict is removed, the sickness disappears. If people on Earth experience similar symptoms when their visual and vestibular systems disagree, the argument's explanation becomes much more robust.