Q1: The answer is Animalia.
Animal cells don’t have cell walls. A cell wall is a structural layer outside the cell membrane found in Archaea, bacteria, plants, and also some fungi and algae. Its major function is structural support ant protection against environmental stress and infection.
Q2: The answer is Eubacteria.
The main difference between a eukaryotic and a prokaryotic cell is the presence of a nucleus and organelles in eukaryotic cell and their absence in prokaryotic cell. Plantae, Animalia, and Protista are eukaryotes, so the right choice is Eubacteria which lack in nuclei and complex cell structures.
Q3: The answer is Protista.
Since it has a nucleus, it cannot be Eubacteria. Among the Eukaryotes, it could belong to the kingdom of Protista, Fungi, Plantae and Animalia. Since it is unicellular organism and is able to photosynthesize, it could belong only to the kingdom of Protista