Question

Match the columns

Phylum	Characteristics
i)Mollusca	A) collar cells
ii)Hemichordate	B) mantle
	C)trunk

Answer 1

Hint: Mollusca is the second largest phylum present. They are usually found in marine water and freshwater. They have an organ-system level of organization. Hemichordates are bilaterally symmetrical organisms and are triploblastic in nature. They have a true body cavity present.

Complete answer:
-Mollusk or mollusc have organ levels of body organization. The characteristic feature of molluscs is the presence of a mantle and a body cavity. The body cavity is used for breathing and excretion. Many organisms of this phylum also have calcareous shells present on them. The body of the molluscs can be divided into three parts: a head, visceral mass, and mantle. The head is the sensory part of the body. It also helps in the locomotion of the animal. The visceral mass contains most of the organs present in the body. The mantle covers visceral mass and provides protection to it by the release of the shell if present in their body. The anus and genitals open into the mantle cavity of the body of the organism. There is also the presence of a radula for rasping the tongue. They also have large complex kidneys present.
-Hemichordate has its body divided into three parts which are the anterior prosome, the intermediate mesosome, and the posterior metasoma. It can be divided into anterior proboscis, intermediate collar, and posterior trunk. The proboscis is used for the locomotion by organisms and is also used for the collection of food particles. The mouth of the organism is located between the proboscis and collar. The trunk is the longest part of the body. It consists of major organs present in the body of organisms. They have an open circulatory system.
So, the answer is ‘(i)-B and (ii)- A, C’.

Note: The distinct character of Mollusca is the presence of mantle which helps in the formation of the shells outside the body of the animal. They use shells for protection. Hemichordate consists of acorn worms which generally live in burrows.