dna sequence is the basis of grouping organisms in
karyotaxonomy
cytotaxonomy
chemotaxonomy
phenetics 

explain why ans is 3??

Dear student, Identifying and classifying the organism on the basis of similarities and dissimilarities in their biological composition is called chemotaxonomy. Chemical constituents of Plants are specific and stable and hence do not change easily. Hence dna sequence is the basis of grouping organisms in chemotaxonomy. Thanks and regards