Abnormalities in shellfish are common. In one type of abnormality, the DNA of the shellfish contains an extra nitrogen base pair. This would be a result of

Gene mutation

Explanation: Gene mutation is a biological term used to describe the change in the genetic sequence or nucleotide composition of one or more of the gene composition of an organism, this gene mutation usually leads to abnormalities in the affected organism as described in the above question, the DNA of the shellfish contained an extra Nitrogen base pair which has made it different from other shelf fishes.

he movement of air through earth's or any planet's atmosphere is called wind, and the main cause of earth's winds is uneven heating by the sun. this uneven heating causes changes of atmospheric pressure, and winds blow from regions with high pressure to those with low pressure.

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igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.