In this task, you're given an open-domain question. Your task is to provide an answer to the given question. There is only one unique answer for each question. Your answer should be short, and refer to an entity, date, number, etc. Do not put your answer in the context of a sentence.

How many mammal species live wild in ireland today?
60

Who plays zoey in day of the dead bloodline?
Sophie Skelton

Who proposed the coupling and repulsion theory of linkage?

John Burdon Sanderson Haldane