I believ the answer is c but if not i am super super sorry!!!
Answer:
The added carbon is supplied by acetyl CoA and the 2 eliminated carbons are released as CO2.
Explanation:
TCA cycle or citric acid cycle occurs in the mitocondrial matrix.
The ist step of TCA cycle deals with the formation of citrate molecule bt the addition of Acetyl CoA with oxaloacetate. The acetyl CoA is a 2 carbon compound formed from pyruvate by the catalytic activity of pyruvate dehydrogenase .
The 2 eliminated carbons are released as carbon di oxide or CO2.The CO2 molecule is eliminated during the formation of alpha ketoglutarate from isocitrate .The second CO2 molecule is eliminated when alpha ketoglutarate is converted to succinyl CoA.
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.
They are accepted as true until they are proven false. Once a theory has been tested and it is wrong, then it is no longer true.