Why do we have fingerprints? I would guess reduced friction and increased sensitivity both factor into the answer but what is the advantage (if indeed there is one), in terms of our biology, of having no two fingerprints the same?. Likewise, why are there reoccuring patterns such as the loop, arch or whorl, across the entire species? 

My friend says that if it's acceptable to marry your first cousin, as it is in many cultures, then it should also be acceptable to marry your great grandfather, as you will share a similar amount of genetic material. I'm doubtful about this. How far back would you have to go before sleeping with your ancestor wasn't incest?

The City Centre where I live has just been renewed and yet it is already coated with Bubblegum. Is there anything that eats Bubblegum in the wild? Could a bacteria be developed like Nylonase that digests all this Bubblegum that clogs our pavements?

I was pealing a Pomelo fruit and suprised by the large space in its center. I wonder what fills that space before air goes in when its pealed.

I washed some apples and served them on a hand-carved soapstone platter (see photo). When we began to eat them, we noticed the apples had left blue stains on the plate. What could have caused this?

Tony Wills, London, UK

I washed some apples and served them on a hand-carved soapstone platter (see photo). When we began to eat them, we noticed the apples had left blue stains on the plate. What could have caused this?

Tony Wills, London, UK

A normal healthy humans can maintain constant blood flow to their brain providing that the average arterial blood pressures is between 50 and 150 mmHg. Above 150 mmHg there is a risk that blood flow becomes too high, which can potentially cause a brain haemorrhage.  Below 50mmHg and there is a risk that blood flow will be inadequate to perfuse the brain.

Giraffes can grow to heights of 5m.  I think that the difference in cerebral blood pressure between standing fully erect and bending down to ground level to drink would be over 360mmHg. 

I have heard that giraffes have a system of one way valves in their neck veins to prevent pressure overload in the venous system when bending down to drink but it would be impossible to achieve this with their arteries because the blood has to travel in the direction of the head.  

How do giraffes maintain constant brain blood flow over such a huge range of blood pressures?

How do their cerebral arteries cope with such high pressures without bursting?