We sleep so that our brain can repair and refresh itself.
All 17 reporters have been detained for months.
Researchers say they have a lot more work to do.
Mars Desert Research Station in Utah
Heat waves appear across the tarmac at Sky Harbor International Airport.
Columbia University graduation
Temperatures climb to near-record highs.
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.”