What is {instance of} of {horse} that is {of} is {Equus caballus} ?
Which is the best comparative horse as  an example of Equus caballus?
What kind of horse is an example of Equus caballus?
SELECT ?a WHERE { ?u rdf:type ?a . resource:horse rdf:type ?u . ?u property:of resource:Equus_caballus }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q726> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P31> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P642> <http://wikidata.dbpedia.org/resource/Q10758650>
} 

SELECT ?obj WHERE { wd:Q726 p:P31 ?s . ?s ps:P31 ?obj . ?s pq:P642 wd:Q10758650 }