Electoral battles

20 science questions for US presidential candidates

A coalition of US groups representing more than 10 million scientists and engineers published 20 questions on Wednesday they want every US presidential candidate to answer ahead of November's vote.

The questions range from how to support vaccine science, to defining the scope of America's goals in space, to the candidates' views on climate change and what would they would do about it.

Stances on nuclear power, protecting the world's oceans, reducing the human and economic costs of mental illness, and the controversy over visa programs that allow highly skilled immigrants into the United States also feature in the list, made public by the American Association for the Advancement of Science (AAAS).