MCQ
For two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion: Nucellus functions as a nutritive tissue.
Reason: Nucellus is always exhausted completely during development of embryo sac.
  • A
    Both assertion and reason are true, and reason is the correct explanation of assertion.
  • B
    Both assertion and reason are true, but reason is not the correct explanation of assertion.
  • Assertion is true, but reason is false.
  • D
    Both assertion and reason are false.

Answer

Correct option: C.
Assertion is true, but reason is false.
The body of the ovule consists of a mass of parenchymatous cells named nucellus. The nucellus is mostly consumed by the developing embryo sac or endosperm. But in some plants it persists in the mature seed as a nutritive tissue. The persistent nucellus is called perisperm.

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The anther is a four$-$sided structure consisting of four microsporangia located at the corners, two in each lobe. $TI1e$ microsporangia develop further and become pollen sacs. In a transverse section, a typical microsporangium appears near circular in outline. It is generally surrounded by four wall layers$-$the epidermis, endothecium, middle layers and the tapetum.
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Select the option that correctly fills the blanks.
S. No
$A$ $B$
$(a)$
Four
Two
$(b)$
Two
One
$(c)$
Two
Two
$(d)$
Four
One
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$(a)$
$A-$Middle layer
$B-$Endothecium
$C-$Tapetum
$(b)$
$A-$Endothecium
$B-$Tapetum
$C-$ Middle layer
$(c)$
$A-$Endothecium
$B-$Middle layer
$C-$Tapetum
$(d)$
$A-$Tapetum
$B-$Middle layer
$C-$Endothecium
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  2. Mechanical.
  3. Nutrition.
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  4. All of these.