['species', 'respond', 'EmptyParameter', 'EmptyParameter', 'EmptyParameter']
["Synset('category.n.02')", 'respond-113', 'EmptyParameter', 'EmptyParameter', 'EmptyParameter']
They are only interested in studying how physical species respond to the unknown.
<PRP> are only Synset('interested.a.01') in studying how Synset('physical.a.02') Synset('category.n.02') respond to the Synset('unknown.a.01').