Question

who proposed three kingdoms system of classification system and what objections were raised against this system​

Answer 1

Three kingdom classification system was put forward by Haeckel in order to overcome the objections and limitations of the Two Kingdom System of Classification.

Haeckel suggested that the inconsistencies of the two-kingdom system could be avoided by the recognition of a third kingdom, and he proposed Protista as a new kingdom to accommodate organisms exhibiting characters either common to both plants and animals, or unique to their own.

Haeckel’s three kingdoms were Animalia, Plantae, and Protista.