Final answer:
The phrase that suggests a desire for adventure in Eugene O'Neill's 'Beyond the Horizon' is "the joy of wandering on and on," symbolizing a yearning for exploration and freedom.
Step-by-step explanation:
In the given excerpt from Act 1 of Eugene O'Neill's "Beyond the Horizon," the phrase that suggests Robert's desire for adventure through travel is: 2) "The joy of wandering on and on." This particular phrase evokes a sense of delight and excitement associated with continuous exploration and movement. It implies a longing for the thrill that comes with venturing into new and unexplored territories. Robert's desire for the "joy of wandering" suggests a fascination with the unknown and a yearning for the experiences that come with traveling to different places. The other options also convey a sense of wanderlust, but option 2 more explicitly captures the idea of adventure through continuous wandering.