Answer:
RNA
Explanation:
CRISPR system was discovered by a Japanese scientist. Naturally <u>bacteria and many other prokaryotes</u> have <u>CRISPR system in their genome</u> which they use as a<u> self defense against a pathogen</u> which is invading them. It consists of<u> inter spaced, short palindromic nucleotide repeats </u>which <u>encode a guide RNA (gRNA)</u>. This guide RNA (gRNA) recognizes the<u> target sequence</u> on the pathogen. The <u>gRNA is followed by Cas9 enzyme</u> which along with the gRNA plays a very important <u>role in breaking genome</u> of the pathogen. Once the target gene is cut down the rest of the DNA can be rejoined by<u> non homologous end joining. </u>
But nowadays, scientists are using this system for <u>genome editing</u> and <u>incorporating desired gene</u> between the two ends which are cut down by <u>CRISPR Cas9 system.</u>
You need to be way more specific
The oldest fossil evidence that geochemists have been able to find in deposits in Pilbara, Australia, and South Africa have been dated to 3.5 bya. In addition, organic compounds that may be the result of those produced by organisms have been dated, also in Greenland, to 3.8 bya.
You've answered it yourself: its called the crust.
