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Q101.
What is the primary importance of classifying the more than a million animal species described so far? __________
[Animal-Kingdom] [class-xi]
Correct option: C [ To assign a systematic position to newly described species ]
Remark: The source states that the classification of over a million species is important because it helps in assigning a systematic position to newly described species, making their study more organized.
Q102.
Which level of organisation is characterized by cells arranged as loose cell aggregates, as seen in sponges? __________
[Animal-Kingdom] [class-xi]
Correct option: C [ Cellular level ]
Remark: In sponges, the cells are arranged as loose cell aggregates, which is defined as the cellular level of organisation. This is the most primitive level among multicellular animals.
Q103.
In coelenterates, the arrangement of cells is more complex than in sponges, where cells performing the same function form tissues. This is called the __________.
[Animal-Kingdom] [class-xi]
Correct option: B [ tissue level of organisation ]
Remark: In coelenterates, cells performing the same function are grouped into tissues, which is known as the tissue level of organisation. This is a step above the cellular level.
Q104.
A digestive system with two openings, a mouth and an anus, is called a __________ digestive system.
[Animal-Kingdom] [class-xi]
Correct option: D [ complete ]
Remark: A complete digestive system has two separate openings for the mouth and anus, allowing for a one-way flow of food and more efficient digestion, unlike the incomplete system with a single opening.
Q105.
In which type of circulatory system are the cells and tissues directly bathed in blood? __________
[Animal-Kingdom] [class-xi]
Correct option: B [ Open type ]
Remark: In an open circulatory system, blood is pumped out of the heart into body cavities where cells and tissues are directly bathed in it.
Q106.
What type of symmetry is most commonly found in sponges? __________
[Animal-Kingdom] [class-xi]
Correct option: C [ Asymmetrical ]
Remark: Sponges are mostly asymmetrical, meaning they lack any plane that divides them into mirror-image halves.
Q107.
Which group of animals typically exhibits radial symmetry? __________
[Animal-Kingdom] [class-xi]
Correct option: C [ Coelenterates, ctenophores, and echinoderms ]
Remark: Radial symmetry is found in coelenterates, ctenophores and adult echinoderms where planes through the central axis produce similar halves.
Q108.
Animals that can be divided into identical left and right halves in only one plane are said to have __________ symmetry.
[Animal-Kingdom] [class-xi]
Correct option: D [ Bilateral symmetry ]
Remark: Bilateral symmetry means a single plane (the midsagittal plane) divides the body into left and right mirror-image halves.
Q109.
Animals in which cells are arranged in two embryonic layers, an external ectoderm and an internal endoderm, are called __________ animals.
[Animal-Kingdom] [class-xi]
Correct option: B [ Diploblastic ]
Remark: Diploblastic animals, such as coelenterates, develop from two primary germ layers: ectoderm and endoderm.
Q110.
What is the undifferentiated layer present between the ectoderm and endoderm in diploblastic animals called? __________
[Animal-Kingdom] [class-xi]
Correct option: B [ Mesoglea ]
Remark: Mesoglea is an undifferentiated, jelly-like layer found between ectoderm and endoderm in diploblastic animals like cnidarians.