Because the earth's rotation isn't a perfect circle, so it gets different amounts of sun in certain times
The correct codes are 63267 and 69990.
The codes are given based on the lesion if it is intradural or extradural. In our case here it is extradural cystic structure so that is why it ranges between 63265 to 63268.
We also divide the section of spine depending on where the lesion is being located. Code 63267 describes laminectomy which has evacuation of intraspinal lesion which is found in the lumbar spine.
69990 code documents the use of microscope.
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Answer: Species/Organism
QUICK DISCLAIMER: "I previously said Populations but my answer was reported and removed Imao. Honestly, if someone gives you a wrong answer, don't blame them, blame yourself for not doing it on your own. Keep that in mind."