Fertilizer is crucial to agricultural production, but its increasing use is leaking nitrous oxide, an ozone-deteriorating gas, into the atmosphere. iStockphoto.com hide caption

itoggle caption iStockphoto.com

The coats of domestic dogs vary wildly and can be long, short, straight, wavy, curly or more. Pictured here (left to right) are three breeds with different coat types: Saluki, Vizsla and Samoyed. Tyrone Spady hide caption

itoggle caption Tyrone Spady

These healthy newborn monkeys, Mito and Tracker, developed from embryos containing transplanted DNA. They are named after the dye "mitotracker" used for imaging mitochondria in cells. Oregon National Primate Research Center at OHSU hide caption

itoggle caption Oregon National Primate Research Center at OHSU