Select the correct pair amongst the following

• Spring wood- light colour, high density

• Spring wood - dark colour, low density

• Autumn wood - light colour, high density

• Autumn wood - dark colour, high density

Assertion : Protostele is the simplest stele.

Reason : Protostele is the most advanced type of stele.

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

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

• If assertion is true but reason is false.

• If both assertion and reason are false.

Why are vascular bundles closed in monocots?

• Xylem and phloem are present.

• Xylem and phloem occur in separate bundles.

• Vascular cambium is present between xylem and phloem.

• Vascular cambium is not present.

Assertion : Cork prevents the loss of water by evaporation.

Reason : Cork cells contain tannins.

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

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

• If assertion is true but reason is false

• If both assertion and reason are false

Bark refers to

• phellem + phellogen + phelloderm

• periderm + cortex

• phellem + phelloderm + secondary phloem

• periderm + cortex + pericycle + secondary phloem

86.

Jute fibres deteriorate quickly because

• cellulose content is high

• lignin content is high

• cellulose content is low

• lignin content is low

Assertion: In angiosperms, transport of food and water is more efficient than gymnosperms and pteridophytes.

Reason: In angiosperms longitudinally arranged sieve elements and vessels with perforated end walls are present.

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

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

• If assertion is true but reason is false

• If both assertion and reason are false.

Assertion : In woody stems, the amount of heart wood continues to increase year after year.

Reason : The cambial activity continues uninterrupted.

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

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

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion : Petroplants produce large amount of latex.

Reason : The latex contains long chain hydrocarbons.

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

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

• If assertion is true but reason is false

• If both assertion and reason are false

Which one of the following statements pertaining to plant structure is correct?

• Cork lacks stomata, but lenticels carry out transpiration.

• Passage cells help in transfer of food from cortex to phloem

• Sieve tube elements possess cytoplasm but no nuclei.

• The shoot apical meristem has a quiescent centre