I had a question like this so i'm rolling with (B)
Gills would be the most common sense answer. I took the test and it was correct.
Answer:
Arachnids, crustaceans, myriapods.
Explanation:
Arthropods are animals that form the phylum Euarthropoda. This phylum includes the arachnids, crustaceans, myriapods, and insects. The defining characteristic for an animal to be considered an arthropod is that it has to have an exoskeleton, meaning that the skeleton of the animal is acting as a shell to the body, covering it from the outside.
At present, all of the species of arthropods are small in size, though in the distant past there were speciemens that can be considered as medium-sized or even large. The exoskeleton has its advantages and disadvantages. An advantage is that it is very hard and it covers fully the internal organs, thus protecting them. A disadvantage is that it limits the size to which these animals can grow as the exoskeleton cannot support the weight of the body after certain point.
