Final answer:
Katrina has identified a gene, which is the segment of DNA that contains instructions to make specific chemicals needed by the body and is located on chromosomes within the nucleus.
Step-by-step explanation:
Katrina has identified a gene, which is the distinct portion of a cell's DNA that carries the coded instructions for making a specific chemical required by the body. Genes are found on chromosomes, which are long strands of DNA coiled up with proteins, and they are crucial for encoding the RNA and protein molecules necessary for all life processes. DNA is housed within the nucleus of eukaryotic cells, which serves as the command center containing all genetic instructions crucial for cellular functions.