We sleep so that our brain can repair and refresh itself.
Researchers say they have a lot more work to do.
All 17 reporters have been detained for months.
Mars Desert Research Station in Utah
Heat waves appear across the tarmac at Sky Harbor International Airport.
Temperatures climb to near-record highs.
Columbia University graduation
Evidence suggests potassium may have an effect on hypertension.
Colorado would become the first state to have such a ban.
“Our species is much older than we thought.”