What's more, the mitochondria in cells that generate energy can, in many simple animals, function without oxygen for substantial periods of time. (newscientist.com)
Parts of the brain are unable to develop also if they are left to cry over substantial periods of time. (evolutionaryparenting.com)
Well - designed and supervised administrative internships that allow candidates to engage in leadership responsibilities for substantial periods of time under the tutelage of expert veterans. (wallacefoundation.org)