Some questions I have about mould:

• When I buy a loaf of bread, are the spores already in the bread or are they floating around in the air?
• How many different kinds of mould are there? Do they each specialise in certain hosts?
• Why does mould have that characteristic fuzzy, furry appearance? What’s the purpose of the strings it grows? Why does it come in shades of green, brown, black and white?
• How similar are moulds to mushrooms?
• Why are some moulds so toxic for humans to eat while others aren’t?

and an interesting mould-related link that might answer some of these questsions: How Moulds Are Grown.