Nematodes and arthropods are the largest ecdysozoan phyla. Which of the following statements are true? Select all that apply.

a). Both nematodes and arthropods must molt in order to increase in size.

b). Arthropods possess an open circulatory system.

c). Arthropods are named for their jointed appendages.

d). Nematodes possess a closed circulatory system.

e). Both nematodes and arthropods possess an external covering or cuticle.

f). The cuticle in nematodes lengthens as the animal grows.

g). Both nematodes and arthropods have segmented body plans.

h). Nematodes are acoelomate, whereas arthropods are coelomate.

i). Some nematodes are parasitic on humans.

The correct answer will be-

1. Arthropods are named for their jointed appendages.

2. Both nematodes and arthropods possess an external covering, or cuticle.

3. Some nematodes are parasitic on humans.

4. Arthropods possess an open circulatory system.

5. Both nematodes and arthropods must molt in order to increase in size.

Explanation:

Ecdysozoa is the largest group of animals which includes the largest phylum called the Arthropods and the nematodes along with other small phyla.

The members of this superphylum are characterized by having an outer covering called "cuticle" which protects the animal from the water loss and external environment.

The members moult while they grow in size and shed their cuticle and forms a new cuticle layer after moulting.

Nematodes are pseudocoleomates which are parasitic in nature and can cause elephantiasis which involves swelling of the lower part of the humans.

An arthropod is a group of small organisms which is marked by the jointed legs. Their circulatory system is open circularity system as they lack blood vessels to transport fluid.

Thus, the selected options are correct.