While examining a specimen under the microscope, janet discovers a structure that has some genetic material that has rna but not dna. what is the specimen?

Janet is watching an RNA virus.

Explanation:

Viruses are microorganisms classified according to their DNA or RNA nucleic acids. They are formed by a protein capsule, the capsids and, inside this, there is only DNA or RNA. Accordingly, we can say that Janet is observing an RNA virus under the microscope.

Some viruses are called enveloped because they have the capsid formed by a lipid membrane resulting from the invaded cell plasma membrane.  The capsule is also responsible for the specificity of the virus to adhere to certain cells, this is only possible because they have membrane proteins (receptors) that can fit into their proteins.