Question: What nationality is Martha Constantine-Paton's husband?
Sentence (from "H. Robert Horvitz"): Howard Robert Horvitz (born May 8, 1947) is an American biologist best known for his research on the nematode worm "Caenorhabditis elegans", for which he was awarded the 2002 Nobel Prize in Physiology or Medicine, together with Sydney Brenner and John E. Sulston.
Relevant evidence: Yes