E) characteristics of phylum Insecta:

 1)  Insects are air breathing mostly terrestrial and rarely aquatic arthropods.

 2) Body is divided into three distinct regions head ,thorax and abdomen.

 3) Head consists of six fused segments and bears a pair of antennae and mouth   
    parts adapted for chewing, biting, piercing , sucking ,siphoning or Sponging type.

 4) Thorax consist of three free segments,each bearing a pair of legs and two pairs of
     wings borne on the second and third segments.

5) Abdomen consist of 7to 11 segments and without appendages.

6) Liver is absent  but salivary glands are usually present.

7) Heart is elongated , tubular and is divided into eight chambers situated in the  
   abdomen.

8) Respiration is carried by branched tracheae.

9) Excretion is carried by Malphigian tubules.

10) Sexes are separate.