Who classified plants into $24$ groups based on their sexual characteristics?

Which of the following systems of classification involves the usage of one or a few morphological characters for the grouping of organisms?

The replacement of two-kingdom grouping by five-kingdom classification was proposed in the year

Which classification system was proposed by $R.H. Whittaker$?

Which of the following is a domain of eukaryotic organisms?

Who was the earliest to attempt a more scientific basis for classification? He used simple morphological characters to classify plants into trees,shrubs,and herbs.