Lame questions indeed

had so much fun laughing our lungs out at school today
cause there's these lame questions posted by my close buds

1] egg yolk IS white or egg yolk ARE white ?

2] what is the colour of the teeth of a new born INDIAN BABY ?

3]where do survival peeps go after they die ?

and i wonder .........

why is a dog named dog but not tiger/lion/leopard/panther/cat ?
my friend answered me that's because its a dog and their "dog" enough
btw, how do you know its called a dog before you name it a dog ?
why do you call them DOGS ?
can anyone tell me ?