A geneticist studied the genome of a child. The geneticist discovered that the genetic material of the child had three copies of chromosome 13.
How would the geneticist learn this type of information about the child's genome?

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

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.