Hard calcium carbonate structures are used as skeleton by
(a) Echinodermata
(b) Protochordata
(c) Arthropoda
(d) Nematoda
1 Answers
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What are homologous structures? Give an example. Is it necessary that homologous structures always have a common ancestor?
Structures which have a common basic structure but perform different functions are called homologous structures. e.g. fore limbs of reptiles, amphibians and mammals. Yes, they have common ancestor but variously...
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Water vascular system is the characteristic of which group of the following: (a) Porifera (b) Ctenophora (c) Echinodermata (d) Chordata
Ans. C- Echinodermata.
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In which group of animals, coelom is filled with blood? (a) Arthropoda (b) Annelida (c) Nematoda (d) Echinodermata
(a) Arthropoda
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The feature that is not a characteristic of protochordata? (a) Presence of notochord
(c) Jointed legs
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Real organs are absent in (a) Mollusca (b) Coelenterata (c) Arthropoda (d) Echinodermata
(b) Coelenterata
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Bone matrix is rich in (a) fluoride and calcium (b) calcium and phosphorus (c) calcium and potassium (d) phosphorus and potassium
(b) calcium and phosphorus
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Write the chemical formula of the following: (a) Magnesium chloride (b) Calcium oxide (c) Copper nitrate (d) Aluminium chloride (e) Calcium carbonate
(a) Magnesium chloride →MgCl2 (b) Calcium oxide →CaO (c) Copper nitrate →Cu(NO3)2 (d) Aluminium chloride →AlCl3 (e) Calcium carbonate →CaCO3
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On heating calcium carbonate gets converted into calcium oxide and carbon dioxide. (a) Is this a physical or a chemical change?
(a) Chemical change (b) Acidic and basic solutions can be prepared by dissolving the products of the above process in water CaO+H2O →Ca(OH)2 (basic solution) CO2 + H2O→H2 CO3 (acidic solution)
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Bones are hard structures and cannot be bent. But, we can still bend our elbow, knee, etc. How is this possible?
Elbow and knee are not made up of a single bone, but two or more bones which are joined to each other by a joint (Hinge joint). This joint along...
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Marble contains ,(A) calcium hydroxide (B) calcium chloride (C) calcium carbonate (D) calcium oxide
(C) calcium carbonate Marble contains calcium carbonate and its chemical formula is CaCO3.
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