Answer:
The correct answer is - protist.
Explanation:
Protist is a single-celled eukaryote that contains organelles. It is the last common ancestor of all animals as is consider as most primitive animal cells as it has no cell wall but contains the nucleus and other double-membrane organelles. The protists are the cell that distinguishes fungus, plant cells, and animal cells into these three different kingdoms.
Thus, the correct answer is - protist.