• 

  Now Playing
  Air pollution particles have been found in mother's placenta, study says

  00:55
• 

  Now Playing
  Can hurricanes literally give you a headache?

  01:11
• 

  Now Playing
  3 reasons you should eat more Japanese food

  01:12
• 

  Now Playing
  What is a water allergy?

  01:00
• 

  Now Playing
  What taking a vacation does to your body and brain

  01:02
• 

  Now Playing
  Scientists think they have found the reason why people are left-handed

  01:08
• 

  Now Playing
  What every parent needs to know about flu shot season

  00:38
• 

  Now Playing
  Dozens fall sick in India after worst flooding in a century

  01:12
• 

  Now Playing
  Judge denies request to end aid for Puerto Ricans fleeing from Hurricane Maria

  00:45
• 

  Now Playing
  112 Ebola cases reported as outbreak escalates

  00:39
• 

  Now Playing
  5 healthy foods that help curb your hunger

  00:32
• 

  Now Playing
  New hair color trends for fall

  00:32
• 

  Now Playing
  Red tide putting businesses and employees in an economic crisis

  01:00
• 

  Now Playing
  Are you allergic to mosquito bites?

  00:42
• 

  Now Playing
  5 healthy back-to-school snacks your kids will love

  01:05