The method of categorising organisms into different groups on the basis of similarities and differences is known as classification.
It simplifies the study of a wide variety of organisms in a systematic manner.
Five-kingdom classification:
R.H. Whittaker proposed the five-kingdom classification in 1969.
This system of classification was based on specific characteristics like mode of nutrition, organization of the thallus, structure of the cell, phylogenetic relationships and reproduction.
This type of classification includes five kingdoms namely Monera, Protista, Fungi, Plantae and Animalia.