Welcome to this Friday's round-up of the week's top questions on The Last Word.

Questions this week have been overwhelmingly biological. Today, we're wondering what is happening to symphylan's tastebuds. When drinking well water after chlorinated water, symphylan experiences a strange bitter taste. Can you explain these tastebud troubles?

For a bit of entomology, Alisong found a 5.5-centimetre-long moth on her gatepost. There's been quite a discussion about it - take a look to find out what it is, or add more heat to the debate.

This one's not for the faint-hearted, but it's pretty egg-citing: take a look at what's hiding in the white of these chickens' eggs.

Ed_Harman was puzzled by his ability to sleep until exactly midday every day, irrespective of the time he goes to bed. Some of our Last Worders help explain why he awakes at the same time every day.

The exception to the biological theme was celliottuk's question: if you want to stop fizzy drinks from going flat, would it help to squash the bottles that contain them?The Last Word members strike again with explanations of what gaseous shenanigans are going on in those bottles.

If you have a better answer for any of this week's questions, roll up your sleeves and get stuck in. Otherwise, sit back and enjoy the explanations!

All the best,

Kat

Letters and comments editor, New Scientist

I often wake up just a minute before my alarm goes off, even though I dont always set it for the same time. How does my body know what time it is or that it is time to wake up?

Since the end of exams an alarm clock has become superflulous. However, the past week i have gone to sleep between 11.30pm and 3.30, yet I have always woken up just in time to see my clock turn to midday. How does this happen?

As a child, if I was hot at night I would turn my pillow over to find it cool and the provider of temporary relief.

I only rarely feel a need to get that cool sensation these days, but why would the pillow be cool?

Does being able to get by on little sleep correlate with any characteristics?

I have been able to recall several dreams each night, some with vivid clarity and detail, since i was a teenager and thought this was because i sleep so deeply. A friend disagrees and says that i must be a bad sleeper or wake several times in the night because you cannot remember your dreams if you sleep well. However I do sleep pretty deeply most of the time.Who is right?

This question is from a new mother; but her husband would like to know, too ...