How many hours should a 13 year old girl sleep every night?

my cousin, shes 13. her eyes r purple, she said coz she didnt have enough of sleep. so ans plz :D

I am allergic to dogs, cats, guinea pigs, pollen, dust and more! I need a medicine that is good for me and works for 24 hours

I swear, i'm so mad.... and worried. What would happen if she doesn't need them?

During puberty is it possible for a 13 year old to have problems with their short term memory?

what's the avarage size peinus for a 13 year old?

I'm kinda short for 13 and I just want to know...

I'm 13 and I'm 6 inches long and 5 inches wide. Is this small?

Hi, I'm 13 years old and my height is just really.. well I sometimes hate it. I'm about 4"6 or 4"7 and I KNOW your are probab...

Well I usually have a hard time sleeping lately, I just love the night lol and I like staying up late, but whats the least am...

Mainly on school nights, i wake up every two hours, check the time, check my phone, drink gatorade, then go back to bed. I'm ...