What are the most significant differences between the lancelet and invertebrates?

What are the most significant differences between the lancelet and invertebrates? Write down the similarities between Lanzenik and fish. What are the most progressive traits in fish in comparison with the lancelet? What are the features that allowed the fish to adapt to life in the water?

What distinguishes lancelet from invertebrates is the presence of an internal skeleton (chord), as well as a tubular-type nervous system. The similarities between the lancelet and fish are that they belong to vertebrates that have adapted to life in the water, the presence in the physique of such sections as the trunk, tail, unpaired limbs, the presence of a large number of glands on the integument, which abundantly wet the body with mucus. The structure of the digestive system has similar sections: mouth, pharynx, intestines. The respiratory system is represented by the gills. Closed type of circulatory system, one circle of blood circulation. The nervous system is characterized by the presence of a neural tube on the dorsal side. Progressive signs that have arisen in fish are the appearance of an inner ear and paired fins. What helped fish adapt in the aquatic environment: streamlined body shape, scales, lateral line, fins, swim bladder, gills.