News Main Animals Archaeology Dinosaurs Earth History Human Animal Space Tech   iStockPhoto |   Perfect Sponge Structure Echinoderms, like sea urchins, have calcium carbonate skeletons that may be ideal for absorbing C02. | Discovery News Video   « back to article

advertisement

our sites

• Animal Planet
• Curiosity
• Discovery Channel
• Discovery Kids
• Discovery Fit & Health
• HD Theater
• Investigation Discovery
• Military Channel
• Oprah Winfrey Network
• Planet Green
• Science Channel
• TLC
• Turbo
• Velocity

• Consumer Guide Auto
• Consumer Guide Products
• Discovery Education
• Discovery News
• Discovery Retreats
• HowStuffWorks
• MyDiscovery
• Petfinder
• Student Competitions
• TreeHugger

video

• Discovery Channel Video

 

mobile

• Mobile Applications
• Wallpaper & Ringtones
• Mobile Video
• Mobile Web
• Text Alerts

shop

• Discovery Store
• DVDs & Books
• Custom Gear
• Toys & Games
• Gift Sets
• Sale
• Discovery Adventures
• Student Adventures
• Discovery TS
• Discovery Corporate Sales

stay connected

• Email Newsletters
• RSS
• Twitter
• Facebook

corporate

• Discovery Communications, LLC
• Viewer Relations
• Advertising
• Careers @ Discovery
• Privacy Policy
• Visitor Agreement

Image Credits iStockPhoto |

Copyright © 2012 Discovery Communications, LLC. The number-one nonfiction media company.