The main criteria used for Five Kingdom Classification proposed by R.H. Whittaker (1969) included :

A. Cell structure

B. Body organization
C. Presence of flagellum
D. Reproduction
E. Phylogenetic relationships

Choose the correct answer from the options given below :

The Five‑Kingdom system introduced by R.H. Whittaker in 1969 was based on four fundamental biological criteria.

1. Cell structure – Whether the organism is prokaryotic or eukaryotic, and the presence of membrane‑bound organelles.

2. Body organization – The overall organization of the organism (e.g., unicellular, colonial, filamentous, or multicellular).

3. Reproduction – The mode of reproduction, such as sexual versus asexual, and the complexity of the life cycle.

4. Phylogenetic relationships – Evolutionary lineage and shared ancestry, reflecting how groups are related on the tree of life.

These four criteria together distinguished the five kingdoms (Monera, Protista, Fungi, Plantae, Animalia). The presence of a flagellum, while useful for identifying certain taxa, was **not** one of Whittaker’s main classification criteria.

Therefore, the correct combination of criteria is A, B, D and E only.