NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions


Age of a tree can be estimated by

  • its height and girth

  • biomass

  • number of annual rings

  • diameter of its heartwood


number of annual rings

Age of a tree can be estimated by number of annual rings. The two kinds of woods that appear as alternate concentric rings, constitute an annual ring heartwood comprises dead elements with highly lignified walls that give mechanical support to the stem. The height and girth of a tree increases due to the activity of vascular cambium.


Interfascicular cambium develops from the cells of

  • medullary rays

  • xylem parenchyma

  • endodermis

  • pericycle


medullary rays

In dicot stems, the cells of cambium present between primary xylem and primary phloem is the intrafasicular cambium. The cells of medullary rays, adjoining these intrafascicular cambium become meristematic and form the interfascicular cambium. 

In dicot roots the innermost layer of the cortex is called endodermis. Next to endodermis lies a few layers of thick-walled parenchymatous cells called as pericycle.


Read the following statements (IV) and answer the question which follows them

I. In liverworts, mosses and ferns gametophytes are free living.

II. Gymnosperms and some ferns are heterospores.

III. Sexual reproduction in Fucus, Volvox and Albugo is oogamous.

IV. The sporophyte in liverworts is more elaborate than that in mosses.

How many of the above statements are correct?

  • One

  • Two

  • Three

  • Four



Statement I, II and III are correct.

In IV statement- sporophyte in mosses is more elaborate than in liverworts.

In V statement- Pinus is a monoecious plant, producing male and female cones every year.

In Marchantia, plant body is strictly dioecious and isomorphic. Sex organs are found in specialised sexual receptacles called anthridiophore and archegoniophore.


Which one of the following is not a correct statement?

  • Herbarium houses dried, pressed and preserved plant specimens

  • Botanical gardens have collection of living plants for reference

  • A museum has collection of photographs of plants and animals

  • Key is a taxonomic aid for identification of specimens


A museum has collection of photographs of plants and animals

Museums have collection of preserved plants and animal specimens for study and reference specimens are preserved in the containers in preservative solutions.

Herbarium is a store house at collected plant specimens that are dried, pressed and preserved on sheets.

Botanical gardens have collection of living plants for reference.

Key is a taxonomic aid for identification of plants and animals based on the similarities and dissimilarities.


Select the wrong statement.

  • Isogametes are similar in structure, function and behaviour

  • Anisogametes differ either in structure, function and behaviour

  • In oomycetes female gamete is smaller and motile, while male gamete is larger and non-motile

  • Chlamydomonas exhibits both isogamy and anisogamy and Fucus shows oogamy


In oomycetes female gamete is smaller and motile, while male gamete is larger and non-motile

Oomycetes or egg fungus include water moulds, white rusts and downy mildews. In these, female gamete is smaller and motile, whereas male gamete is larger and non-motile. 

Isogametes are found in algae like Ulothrix, Chlamydomonas, Spirogyra, etc., which are similar in structure, function and behaviour.

Anisogametes are found in Chlamydomonas in which one gamete is larger and non-motile and the other one is motile and smaller.

Oogamy is the fusion of non-motile egg with motile sperm. The gametes, differ both morphologically as well as physiologically. It occurs in Chlamydomonas, Fucus Chara, Volvox, etc.


Among bitter gourd, mustard, brinjal, pumpkin, China rose, lupin, cucumber, sunnhemp, gram, guava, bean, chilli, plum, Petunia, tomato, rose, Withania, potato, onion, aloe and tulip, how many plants have hypogynous flower?

  • Six

  • Ten

  • Fifteen

  • Eighteen



Bitter gourd, Mustard, Brinjal, Pumpkin, China rose, Lupin, sunnhemp, Gram, Bean, Chilli, Petunia, Tomato, Withania, Potato, Onion, Aloe and tulip are all hypogynous flowers.

Hypogynous flower Perigynous flower Epigynous flower
Gynoecium present above all other floral parts Gynoecium present in the centre Ovary enclosed by thalamus and gets fused with it
Ovary is superior Other part almost at same level Other parts above ovary
  Ovary half inferior eg, Plum, rose Ovary inferior eg, Guava, cucumber


lsogamous condition with non-flagellated gametes is found in

  • Chlamydomonas

  • Spirogyra

  • Volvox

  • Fucus



lsogamy is found in Spirogyra in which both gametes are non-motile.

In Chlamydomonas, all three conditions, isogamy anisogamy and oogamy are found. Both motile and non-motile gametes are found.

In Volvox and Fucus, oogamy is present, where non-motile egg fuses with motile sperm.


In China rose the flowers are

  • actinomorphic, hypogynous with twisted aestivation

  • actinomorphic, epigynous with valvate aestivation

  • zygomorphic, hypogynous with imbricate aestivation

  • zygomorphic, epigynous with twisted aestivation


actinomorphic, hypogynous with twisted aestivation

Actinomorphic or star-shaped can be divided into 3 or more identical sectors, which are related to each other by rotation about the centre of the flower, e.g., China rose.

Zygomorphic flowers can be divided by only a single plane into two mirror image halves, e.g., orchids.

Valvate aestivation The sepals or petals in a whorl just touch one another at the margin, e.g., Calotropis

Twisted aestivation One margin of the appendage overlaps that of the next one, e.g., China rose.

lmbricate aestivation the margins of sepals or petals overlap but not necessarily in specific direction, e.g.Cassia.


Besides paddy fields, cyanobacteria are also found inside vegetative part of

  • Pinus

  • Cycas

  • Equisetum

  • Psilotum



Cyanobacteria within the coralloid roots of Cycas are chemoheterotrophic and specifically adapted to life in symbiosis. Only a few species of cyanobacteria form associations with Cycas.

Pinus is a gymnosperm.

Equisetum belongs to vascular plants and to horse tail family.

Psilotum belongs to division- Pteridophyta and is a fern like plant.


Lenticels are involved in

  • transpiration

  • gaseous exchange

  • food transport

  • photosynthesis


gaseous exchange

Plants have stomata and lenticles involved in gaseous exchange. In stems the living cells are organised in thin layers inside and beneath the bark. They have openings called lenticles.

Transpiration is the evaporative loss of water by plants. It occurs mainly through stomata in leaves.

Food transport occurs by the vascular tissue phloem from a source to a sink.

Photosynthesis is a physico-chemical process by which they use light energy to derive re- synthesis of organic compounds.