The branched sclereids present in hydrophytes are from Biology M

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 Multiple Choice QuestionsMultiple Choice Questions

101.

Assertion : On plotting the length of the root against time, a linear curve is obtained.

Reason : An elongating rout exemplifies arithmetic growth.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are hue but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


102.

Identify the given figures A, B, C, D and E.

                 

  •        A        B        C        D        E
    Marginal Axile Free central Parietal Basal
  •        A        B        C        D        E
    Marginal Parietal Free central Axile Basal
  •        A        B        C        D        E
    Marginal Axile Parietal Free central Basal
  •        A        B        C        D        E
    Marginal Axile Parietal Basal Free central

103. Given figure shows

  • structure of lenticel

  • hydathode showing gaseous vapour exchange

  • fungus reproducing by spore formation

  • algae reproducing by spore formation.


104.

Cleistogamy is leading over anthesis because

  • pollination agent is not required

  • it assures heterozygosity

  • it favours insect pollination

  • it allows xenogamy


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105.

Which of the following is true?

  • Umbel is a racemose inflorescence where all stalked flower aggregate on the flat receptacle

  • Raceme is a racemose inflorescence having main axis shortened & flower born acropetally

  • Spadix is a racemose inflorescence having pendulous spike with main axis much flattened.

  • Spike is a racemose inflorescence having sessile flowers


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106.

The branched sclereids present in hydrophytes are

  • osteosclereids

  • trichosclereids

  • macrosclereids

  • astrosclereids


D.

astrosclereids

Sclereids are highly thickened dead sclerenchyma cells with very narrow cavities. They may also be branched. They provide stiffness to the parts in which they occur. It is of many types : brachysclereids, macrosclereids, osteosclereids, astrosclereids, trichosclereids and filiform sclereids.

Astrosclereids are star-shaped, having various branches or arms. They are found in intercellular spaces of leaves and stems of many hydrophytes like Nymphaea.

Osteosclereid is the sclereid forming the hypodermal layer in many fruits and seeds. It also occurs in the leaves of certain xerophytes.

Trichosclereids are hard needle like branched cells found in some species of plants that serve the purpose of protecting the plant from herbivores.

Macrosclereid is one of the columnar sclereids that often form an outer layer in various fruits and seeds and also occur in the stems of some plants.


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107.

Cut surfaces of fruit and vegetables often become dark because

  • dirty knife makes it dark

  • oxidation of tannic acid in the presence of trace of iron from the knife makes it dark

  • dust of the air makes it dark

  • none of the above.


108.

Ectophloic siphonostele is found in

  • Osmunda and Equisetum

  • Marsilea and Botrychium

  • Adiantum and Cucurbitaceae

  • Dicksonia and Maidenhair fern.


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109.

Composite fruit develops from

  • single ovary

  • inflorescence

  • apocaropous ovary

  • pericarp


110.

Cocoa is the plant from which chocolate is made. Which part is used to extract it?

  • Flower

  • Fruits

  • Seeds

  • Bark


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