Arthropods are invertebrates (animals without a backbone) with jointed legs and a hard exoskeleton (external skeleton). Within the arthropod group are insects (six legs), arachnids (eight legs), crustaceans (variable number of legs) and myriapods (millipedes and centipedes - many legs).
First you have to look at them carefully. Then u have to check if they have a backbone.
by the size
invertebrate - has exoskeleton
An invertebrate.
It is an invertebrate 
no
The octopus is an invertebrate... It has no skeleton.
A bullfrog is not an invertebrate; it has a spine.
seriously? wow....... did you pass 4th grade? invertebrate
An invertebrate doesnt have a backbone. A vertebrate has a backbone.
Crabs are invertebrate!Say the yeti crab has no backbone or spine so it is an invertebrate! Not vertebrate.Yes, all crabs are invertebrates, having an external skeleton (exoskeleton).
invertebrate
An invertebrate.
invertebrate