For the first question, a unicellular eukaryote with autotrophic features (meaning it can produce its own food) will be from either Domain Bacteria and Domain Eukarya, but since Domain Bacteria is not in the choices, then Domain Eukarya is the answer. Domain Archaea are yes, unicellular organisms, but they are not eukaryotes and they do not possess autotrophic features. Domain Eukarya have photosynthetic protozoans (i.e. Diatoms).
For the second question, in Kingdom Fungi, you chose that fungi can either be unicellular or multicellular, which is true, for instance yeast and mushrooms respectively. Fungi are heterotrophic as they cannot produce their own food. The other answer is that fungi are eukaryotic organisms since their cells have a true nucleus and they belong to Domain Eukarya.
For the third question, in Kingdom Protista, you chose that protists can either be unicellular or multicellular, and this is true in the case of amoebas and kelp respectively. Protists can be both heterotrophic and autotrophic. The other answer is that protists are eukaryotic organisms since their cells have a true nucleus and they belong to Domain Eukarya.
