what is a unique characteristics of insects in the order hemiptera check all that apply
The group is very diverse. The majority of species are terrestrial, including a number of important agricultural pests, but some are found in freshwater habitats.
Hemiptera
The group is very diverse. The majority of species are terrestrial, including a number of important agricultural pests, but some are found in freshwater habitats. 
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Hemiptera [SEP] Diversity
Hemiptera is the largest order of hemimetabolous insects (not undergoing complete metamorphosis; though some examples such as male scale insects do undergo a form of complete metamorphosis ) containing over 75,000 named species; insect orders with more species all have a pupal stage (i.e. they do undergo complete metamorphosis or "holometabolism"), Coleoptera (370,000 described species), Lepidoptera (160,000), Diptera (100,000) and Hymenoptera (100,000). The group is very diverse. The majority of species are terrestrial, including a number of important agricultural pests, but some are found in freshwater habitats. These include the water boatmen, pond skaters, and giant water bugs.