i. Cockroach has jointed appendages, which is the characteristic feature of members belonging to phylum Arthropoda.
ii. The body of cockroach is triploblastic, eucoelomate, bilaterally symmetrical, segmented and divisible into head, thorax and abdomen.
iii. Its exoskeleton is chitinous.
Due to the presence of these characteristics, it can be said that cockroach belongs to phylum Arthropoda.