Which domain contains members that lack a cell wall?

What are the drawbacks/limitations of the Two Kingdom classification system?

Which scientist proposed the $3$-domain system of classification?

What was the major contribution of the scientist $R$.$H$. Whittaker in $1969$?

Which of the following statements correctly describes the contribution of Carolus Linnaeus $(1707-1778)$ to biological classification?

Most important criteria used for the present day classification of living organisms is based on