Researchers conducted a series of experiments employing a large number of rats. In each experiment, researchers placed two rats at a time in a large shared compartment. One rat roamed freely in the compartment while the other was confined to a cramped cage whose door could only be opened from the outside. In almost all cases, the unconfined rat chose to open the door, releasing the other rat into the shared compartment, even when offered chocolate as an alternative. The researchers concluded that rats feel empathy and compassion for rats in distress. In order to assess the strength of the researchers' reasoning, it would be most helpful to conduct a second series of experiments in which chocolate was placed inside the small cage with the confined rat in each pair but was accessible to the unconfined rat only when the door is open both rats were rewarded with chocolate if the unconfined rat in a pair opened the door to the cage the door to the small cage could be opened by the rat inside the cage as well as by the rat outside each of the rats in each pair were in equally spacious, comfortable