[omid (OP)]

and how come some people have it and some don't? []

[BenV]

I'm afraid someone beat you to it with this question, Omid!

Have a read here:  http://www.thenakedscientists.com/forum/index.php?topic=11834.0, that should contain the answers you seek...

[omid (OP)]

I'm afraid someone beat you to it with this question, Omid!

Have a read here:  http://www.thenakedscientists.com/forum/index.php?topic=11834.0, that should contain the answers you seek...

ooooooooooooppppppppss!!!!!!!!!!!!
Sorry And Thank you BenV []

[BenV]

No need to apologise!  We can't expect everyone to know every question that's been discussed here, and the search doesn't always come up with exactly what you're after - never be sorry for asking a good question.

[Eric A. Taylor]

For many people smiling makes the dimples