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Q11.
What is the undifferentiated layer present between the ectoderm and endoderm in diploblastic animals called?
[Animal-Kingdom] [class-xi]
Correct option: B [ Mesoglea ]
Remark: Explanation: Mesoglea is an undifferentiated layer present between the ectoderm and the endoderm in diploblastic animals like coelenterates.
Q12.
The body cavity which is lined by mesoderm is called a:
[Animal-Kingdom] [class-xi]
Correct option: C [ Coelom ]
Remark: Explanation: The coelom is the body cavity that is lined by the mesoderm germ layer.
Q13.
Which of the following is an example of a coelomate animal group?
[Animal-Kingdom] [class-xi]
Correct option: D [ Annelids ]
Remark: Explanation: Animals possessing a true coelom are called coelomates. Examples include annelids, molluscs, arthropods, echinoderms, hemichordates, and chordates.
Q14.
Aschelminthes are characterized by the presence of a body cavity that is not lined by mesoderm, known as a:
[Animal-Kingdom] [class-xi]
Correct option: B [ Pseudocoelom ]
Remark: Explanation: In pseudocoelomates like aschelminthes, the body cavity is not lined by mesoderm; instead, the mesoderm is present as scattered pouches. This type of cavity is called a pseudocoelom.
Q15.
The phenomenon where the body is externally and internally divided into segments with a serial repetition of some organs is known as:
[Animal-Kingdom] [class-xi]
Correct option: B [ Metamerism ]
Remark: Explanation: The pattern of external and internal division of the body into segments with serial repetition of organs is called metameric segmentation, and the phenomenon is known as metamerism.
Q16.
What is the rod-like structure derived from mesoderm, formed on the dorsal side during embryonic development in some animals?
[Animal-Kingdom] [class-xi]
Correct option: C [ Notochord ]
Remark: Explanation: The notochord is a mesodermally derived rod-like structure formed on the dorsal side during the embryonic development of some animals.
Q17.
Members of Phylum Porifera are commonly known as:
[Animal-Kingdom] [class-xi]
Correct option: C [ Sponges ]
Remark: Explanation: Members of the Phylum Porifera are commonly known as sponges.
Q18.
The water transport or canal system in sponges is helpful for all the following functions EXCEPT:
[Animal-Kingdom] [class-xi]
Correct option: D [ Anchorage ]
Remark: Explanation: The water transport system in sponges is helpful in food gathering, respiratory exchange, and removal of waste. Anchorage is a function of cnidoblasts in cnidarians.
Q19.
The central cavity in sponges, lined by choanocytes or collar cells, is called the:
[Animal-Kingdom] [class-xi]
Correct option: C [ Spongocoel ]
Remark: Explanation: Water enters the sponge through pores (ostia) into a central cavity called the spongocoel, and exits through the osculum.
Q20.
The body of a sponge is supported by a skeleton made up of:
[Animal-Kingdom] [class-xi]
Correct option: C [ Spicules or spongin fibres ]
Remark: Explanation: The body of a sponge is supported by a skeleton made of structures called spicules or spongin fibres.