Question: How does CRISPR-Cas9 work? Need Assignment Help? Group of answer choices Scientists use a bacterial enzyme to cut out a gene from a strand of DNA and replace it with a gene of their choice. Scientists use a eukaryote exonuclease enzyme to cut out a gene from a strand of DNA and replace it with a gene of their choice. This is because eukaryote enzymes are needed to modify DNA in plants, fungi, and animals. Scientists use the PCR method to amplify a specific gene in a segment of DNA. Scientists use a pair of microscopic scissors under a microscope to cut out a gene from a strand of DNA and replace it with a gene of their choice.