'Gymnosperm' have how many species?

• 1000

• 900

• 640

• 300

Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms

• Perianth and no integuments

• Embryo development and apical meristem

• Absence of resin duct and leaf venation

• Presence of vessel elements and absence of archegonia

143.

Pick the correct group consisting of all genera exhibiting homospory

• Lycopodium, Psilotum, Selaginella, Equisetum

• Equisetum, Pteris, Salvinia, Psilotum

• Salvinia, Pteris, Lycopodium, Selaginella

• Equisetum, Psilotum, Lycopodium, Pteris

Which of the following are homosporous pteridophytes?

I. Selaginella

II. Lycopodium

III. Salvinia

IV. Equisetum

• I and IV only

• II and III only

• II and IV only

• III and IV only

Assertion: Endomycorrhiza of forest trees contribute to the efficient nutrient cycling in tropical forest ecosystems.

Reason: The fungi that formendo-mycorrhizal associations with plants make nutrient ions available to them.

• 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.

Match the following and select correct option.

  Column1        Column2

A. Pteris           1) Gymnosperm

B. Cycas           2) Bryophyte

C. Sphagnum    3) Algae

D. Sargassum   4) Pteridophyta

• A-(4), B-(2), C-(1), D-(3)

• A-(4), B-(1), C-(2), D-(3)

• A-(2), B-(3), C-(4), D-(1)

• A-(1), B-(4), C-(3), D-(2)

Which of the following groups of algae produces algin?

• Phaeophyceae and Chlorophyceae

• Rhodophyceae and Phaeophyceae

• Chlorophyceae and Rhodophyceae

• Phaeophyceae only

Assertion: Presence of large amounts of nutrients in water body causes excessive growth of planktonic algae.

Reason: It is due to biomagnification.

• 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 : Sphagnum is slowly carbonised, compressed and fossilised over thousands of years to produce a dark spongy mass called peat.

Reason : Peat helps to keep soil porous and it also improves water holding capacity of the soil.

• 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 of the given genera is homosporous

• Cycas

• Pinus

• Selaginella

• Lycopodium