What is cardiac arrest?

Buffalo Bills player Damar Hamlin suffered cardiac arrest while on the field Monday night. Cardiologist Dr. Shukri David explains what that means, and what could have caused it.

Scientists find signs of Alzheimer's in dolphin brains

In total, 22 dolphin brains were studied in which researchers noted that the animals presented alterations in their brain chemistry, changes most commonly found in humans who have Alzheimer's.