This question tests measurement interpretation using an ocular micrometer, a skill often assessed on the NEX Science exam. An ocular micrometer is a scale placed in the eyepiece of a microscope and must be interpreted based on the given scale value. In this problem, each division equals 25 micrometers. By carefully counting the number of divisions spanned by the oval in the image, the oval covers8 divisions. To find the total length, the number of divisions is multiplied by the micrometer value per division: 8 × 25 micrometers = 200 micrometers. The other answer choices represent common calculation errors, such as counting too few or too many divisions or using an incorrect multiplication factor. The key to these questions is slow, accurate counting and correct unit conversion. The NEX exam frequently includes microscopy-based questions to assess practical lab interpretation skills.

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