Question

fill in the blank question
the sequencing of small subunit ribosomal
genes has become a vital method for inferring microbial phylogenies and making
taxonomic assignments.

Explanation:

Small subunit ribosomal RNA (16S rRNA in prokaryotes, 18S rRNA in eukaryotes) genes are universally conserved in microbes, with variable regions that allow for phylogenetic analysis and taxonomic classification, making their sequencing a standard method for this purpose.

Answer:

RNA