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• s  having a narrow mouth

• One can buy plastic squeeze bottles for catsup, but first one has to extract the catsup from the narrow-mouthed bottle.

News & Articles

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• One worm, two mouths
  Depending on the environment in which the worm grows, the larva of the roundworm Pristionchus pacificus develops into either a wide-mouthed predator or a narrow-mouthed bacteria eater. A team of researchers has now discovered a developmental biological switch that determines the worm's mouth form.
  Nov. 7, 2013 - Science Daily
• 1 worm, 2 mouths
  ( Max-Planck-Gesellschaft ) Depending on the environment in which the worm grows, the larva of the roundworm Pristionchus pacificus develops into either a wide-mouthed predator or a narrow-mouthed bacteria eater. A team of researchers at the Max Planck Institute for Evolutionary Biology in Tübingen, Germany, headed by Ralf J. Sommer have now discovered a developmental biological switch that ...
  Nov. 7, 2013 - EurekAlert!