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Q41.
The file-like rasping organ for feeding in the mouth of molluscs is called the:
[Animal-Kingdom] [class-xi]
Correct option: A [ Radula ]
Remark: Explanation: The mouth of molluscs contains a file-like rasping organ used for feeding called the radula.
Q42.
In molluscs, the space between the visceral hump and the mantle is called the:
[Animal-Kingdom] [class-xi]
Correct option: C [ Mantle cavity ]
Remark: Explanation: In molluscs, a soft layer of skin called the mantle covers the visceral hump. The space between these two structures is the mantle cavity, which houses the gills.
Q43.
Which phylum's name means "spiny bodied" due to an endoskeleton of calcareous ossicles?
[Animal-Kingdom] [class-xi]
Correct option: C [ Echinodermata ]
Remark: Explanation: The name Echinodermata means "spiny bodied," referring to their endoskeleton made of calcareous ossicles.
Q44.
What is the most distinctive feature of echinoderms?
[Animal-Kingdom] [class-xi]
Correct option: B [ Presence of a water vascular system ]
Remark: Explanation: The most distinctive feature of the Phylum Echinodermata is the presence of a water vascular system.
Q45.
The symmetry of adult echinoderms and their larvae is, respectively:
[Animal-Kingdom] [class-xi]
Correct option: B [ Radial and Bilateral ]
Remark: Explanation: Adult echinoderms are radially symmetrical, but their larvae are bilaterally symmetrical.
Q46.
The excretory organ in Hemichordata is the:
[Animal-Kingdom] [class-xi]
Correct option: C [ Proboscis gland ]
Remark: Explanation: The excretory organ in Hemichordata is the proboscis gland.
Q47.
The body of a hemichordate is composed of:
[Animal-Kingdom] [class-xi]
Correct option: D [ Proboscis, collar, and trunk ]
Remark: Explanation: The cylindrical body of a hemichordate is composed of three distinct parts: an anterior proboscis, a collar, and a long trunk.
Q48.
Which of the following is NOT a fundamental characteristic of Phylum Chordata?
[Animal-Kingdom] [class-xi]
Correct option: D [ A ventral, solid nerve cord ]
Remark: Explanation: Chordates are fundamentally characterized by a notochord, a dorsal hollow nerve cord, and paired pharyngeal gill slits. A ventral, solid nerve cord is a feature of non-chordates.
Q49.
The subphyla Urochordata and Cephalochordata are often referred to as:
[Animal-Kingdom] [class-xi]
Correct option: C [ Protochordates ]
Remark: Explanation: The subphyla Urochordata and Cephalochordata are exclusively marine and are often referred to together as protochordates.
Q50.
In which subphylum does the notochord extend from the head to the tail region and persist throughout life?
[Animal-Kingdom] [class-xi]
Correct option: B [ Cephalochordata ]
Remark: Explanation: In Cephalochordata, the notochord extends from the head to the tail region and is persistent throughout their life.