Moon crater

• German naturalist whose speculations that plants and animals are made up of tiny living `infusoria' led to the cell theory (1779-1851)

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Oken is a lunar crater near the southeastern limb of the Moon . It is normally visible from the Earth , but is foreshortened and within the region of the surface that is subject to libration . To the south and east of this feature is the broad, uneven Mare ...