Traditionally, scientists have identified 4 Kingdoms in the domain Eukaryota: the animals, the plants, the fungi, and the protists. Some scientists argue that the protists actually represent multiple kingdoms, and that there should be many more kingdoms in the domain Eukaryota. Based on the tree, why do some scientists argue for so many kingdoms?

• A. Protists represent a polyphyletic group, so they should not be grouped together.
• B. Protists are a paraphyletic group and modern systematics is usually based on monophyletic groups.
• C. Some protists are more closely related to the archaea and bacteria making them a polyphyletic group.
• D. Protists are a monophyletic group but do not represent a true clade according to modern classification.

Answer: (B)