instruction:
In this task, You are given an open-domain question that can be answered based on factual information. Your task is to provide \*short\* answer (in a few words only) for the given question. The short answer can be one or more entities or it can also be boolean \*yes\* or \*no\*.
question:
when was it discovered that lead was poisonous
answer:
at least 2000 BC


question:
who do the avengers fight in infinity war
answer:
Thanos


question:
who sings the song you are always on my mind
answer:

Gwen McCrae