Question

Rank the following type of worm from greatest to least, by the capability to do complicated movements.

acoelomate Platyhelminthes

pseudocoelomate nematodes

coelomate Annelida

Answer 1

Movement in flatworms is done  by longitudinal, circular, and oblique layers of muscle.

Movement in Nematodes is controlled by  contraction of the longitudinal muscles, the animal moves by thrashing back and forth. No cilia or flagellae are present.

Annelida using longitudinal , circular muscles for movement , and they also have parapodia for locomotion.

Annelida show greatest complicated movements, after that

Platyhelminthes show complicated movements less than annelids, they have cilia and flagella

Nematodes show less compliacted movements, they do not have cilia or flagella