Answer:The correct answer is (a) Ribosomal
Explanation:To determine the relatedness of a new species of microbe to other species, the genes that encode small subunit ribosomal molecules are compared to determine the number of differences in the sequence.
Ribosomal molecules are an essential part of the ribosomes, which are cellular structures responsible for protein synthesis. These molecules are composed of RNA and protein subunits. The small subunit ribosomal RNA (rRNA) gene is highly conserved among different species, meaning that it has regions that are similar or identical across a wide range of organisms. However, it also contains regions that vary between species, and these differences can be used to assess the relatedness or evolutionary distance between species.
By comparing the sequence of the small subunit ribosomal RNA gene in different species, scientists can identify the number of differences in the sequence. The more differences there are, the more distantly related the species are considered to be. This information is useful for studying the evolutionary relationships between different microbes and understanding their evolutionary history.
In summary, to determine the relatedness of a new species of microbe to other species, scientists compare the genes that encode small subunit ribosomal molecules and examine the number of differences in their sequences. This method helps to assess the evolutionary distance between species and understand their evolutionary relationships.