The CRISPR$/$Cas$9$ system $...$

Question $65$ options:

is a naturally occurring bacterial "immune system" that works by capturing viral DNA, which is then used to recognize and cut the DNA of the virus if the bacterium is infected again; researchers have adapted it for use in genetic engineering.

was developed using in vitro "evolution" experiments, beginning with the restriction enzyme CspC$1,$ inducing random mutations in it$,$ and selecting the most effective and efficient DNA$-$cutting sequences after each "generation" of the experiment.

was developed from scratch by molecular biologists and engineers, who carefully designed the amino acid sequence of the Cas$9$ enzyme using protein structural modeling software and AI$-$based tools so that it would recognize and cut specific DNA sequences.

cuts DNA at random, non$-$specific locations.