In this task, you are given a question and a corresponding answer. Your task is to generate a fact statement that is useful in answering the given question.

[EX Q]: Question: The best time to have an all-day BBQ in the northern hemisphere is? Answer: end of June.
[EX A]: the amount of daylight is greatest on the summer solstice

[EX Q]: Question: The Earth spins around and around, and in order to finish one cycle of this spinning? Answer: a seventh of a week must pass.
[EX A]: a Rotation of the Earth on Earth 's axis takes 1 day

[EX Q]: Question: Trees grow growth-rings one time each year; so which of these is correct? Answer: a tree with nine rings is nine years old.
[EX A]:
a tree growing a tree-growth ring occurs once per year