Final answer:
In the 3-domain classification system, Protista is not a domain but a part of the domain Eukarya, making d) Protista the correct answer to the question of which domain wouldn't be included. The correct option is D.
Step-by-step explanation:
In a 3-domain classification system, the domain that wouldn't be included is d) Protista. The three domains of life according to Woese and Fox's phylogenetic tree are Bacteria, Archaea, and Eukarya.
Protista is not a domain, but rather a category within the domain Eukarya that is used to refer to various eukaryotic, single-celled life forms that are not fungi, plants, or animals. Therefore, the correct answer to the question is d) Protista, which is not a stand-alone domain.
Domains Bacteria and Archaea consist of unicellular prokaryotic organisms which do not have nuclei or other membrane-bound organelles. On the other hand, domain Eukarya encompasses organisms with cells that have nuclei and includes kingdoms such as fungi, plants, animals, and protists.