Is it better to stay up late on the night before an exam, learning those last-minute facts, or to get up early and revise in the morning before the exam?

 Andrew Maeer, Exmouth, Devon, UK

Here in Canada, many children grow up in bilingual households. How do their developing brains learn to understand that while 'Hello' and 'Bonjour' mean the same thing, they can only be used within another set of words? Is this a problem? Are there 4 year-olds speaking with a mix of 2 different vocabularies?

When I mow the Dandelions in my lawn they have stems about 6 inches long.  The flowers produced the next, and following days, are very short.  They appear to know the height of the mower and don't extend past that point.  This appears to be a type of learning in a plant since some of the future flowers surely are just a few cells at the time I mowed their parent's heads off (with considerable satisfaction, by the way).