91av

Why don’t trees rot in the ground, while wooden structures do if they aren’t built properly?

Caroline Deforche,

Lichtervelde, Belgium

If humans needed to hibernate, how would civilisation have developed?

William Strudwick,

Grayshott, Hampshire, UK

To answer this question – or ask a new one – email lastword@newscientist.com.

Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.

91av retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format.

Terms and conditions apply.