Ascidians are sac-like marine invertebrates. their larvae have well-developed brains and dorsal nerve cords. this suggests that ascidians should be classified with the a. annelids. b. sponges. c. cnidarians. d. chordates.

Chordates

Explanation: Ascidiacea belongs to the phylum Chordates. They are characterized by outer hard covering known as tunic which is made up of polysaccharide cellulose.

They are found all over the world, usually in the shallow water. They are sac like marine animals. They are invertebrates having almost 2300 species.

Example: sea squirts.

is called echinoderms

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.