Answer:
Archaea
Explanation:
Three main domains exist according to classification, two of these domains are characterized to contain organisms that do not have a membrane bound nucleus, in other words, their single circular genetic material (DNA) is not housed by a nucleus. Instead, the naked DNA is found localized to a central region in the cytoplasm called NUCLEOID. These domains are bacteria and archaea domains and they are termed to be PROKARYOTIC.
These domains also lack membrane bound organnelles i.e their few present organnelles are not bounded by lipid layer. Archaea and Bacteria both have cell walls but what makes up the cell wall is different in both organisms. The organism will most likely be an archaea because it portrays its characteristics being that, an archaea is a unicellular prokaryotic organism with a cell wall. It also has the ability to thrive in extremely harsh conditions like the hot thermal vent described in the question.
