Question

Closed circulatory system occurs in
A. Cockroach
B. Tadpole and fish
C. Mosquito
D. Housefly

Answer 1

Arthropods and molluscs have an open circulatory system whereas chordates have closed circulatory systems. First of all, you should know how many types of circulatory systems are present. There are mainly two patterns seen in the circulatory system, one is open and other one is a closed circulatory system.

Complete answer:
Open circulatory system is that type of circulatory system in which the blood which is pumped by the heart passes through the large vessels in the body cavities i.e., sinuses. This type of circulatory system is seen in arthropods and molluscs.
A Closed circulatory system is that type of circulatory system in which the blood pumped by the heart is always circulated through a closed network of blood vessels and due to this close network of blood vessels the flow of fluid is more precisely regulated and hence it is considered to be more better than the open circulatory system. It is seen in chordates.
If we look at options now, option A is cockroach. It belongs to the phylum Arthropod and there is an open circulatory system present in them therefore this option is incorrect and hence it gets eliminated.
Moving to option B which is Tadpole and fish, this option is correct since tadpole and fish belong to phylum Chordata and in chordates, there is presence of a closed circulatory system. Therefore, this option is the correct one.
Moving to option C which is Mosquito. They belong to the phylum Arthropod and there is an open circulatory system present in them therefore this option is incorrect and hence it gets eliminated.
Last option is D which is housefly. They also belong to the phylum Arthropod and there is an open circulatory system present in them therefore this option is incorrect and hence it gets eliminated.

Thus, the correct answer is option B which is Tadpole and fish.

Note: Since open circulatory system is present in Arthropods and closed is present in chordates so from the given options Cockroaches, Mosquito and Housefly belongs to arthropods and Tadpole and fish belongs to chordates. Therefore, the closed circulatory system occurs in tadpoles and fish.