15 About ----------- percentage of all known species of animals are insect
16 The only invertebrate that can fly is
17 The body of an insect is divided into the head, thorax and
18 Insects carries out gaseous exchange by means of
19 Which of these may not be an adaptive feature of the arthropods?
possession of exoskeleton
pecialised digestive system
20 The phylum echinodermata include all of the following except