You are given a slide of a pathogen that is gram-negative and whose subcellular structures can be observed with a light microscope. what most likely is this pathogen?

This pathogen is most likely to be a fungus.

Explanation:

Fungi are eukaryotic organisms typically having chitin cell walls, but no chlorophyll or plastids. Fungi may be unicellular or multicellular. Eukaryotic pathogens such as fungus are gram-negative when stained with Gram stain. Light microscope is usually used when viewing the results of Gram stain. A gram negative fungus will not retain the dye of the Gram’s stain and it will take on a pinkish color. Subcellular structures of fungi such as endoplasmic reticulum, Golgi apparatus and mitochondrion can also be observed when a fungus is viewed under a light microscope.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.