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(c) Herkogamy

(a) Filiform apparatus helps in absorption conduction of nutrients from nucellus to embryo sac 

(b) It guides the pollen tube into the egg.

(c) Nucellus – Testa and tegma Identify the parthenocarpic fruit

(a) Ovary → Fruit 

(b) Secondary nucleus → Endosperm 

(c) Outer integument of ovule → Outer seed coat (Testa) 

(d) Funicle → Stalk of the seed

Steps involved in fertilization of angiospermic plant:

1. Germination of pollen grain on stigma. 

2. Formation of pollen tube in stigma. 

3. Growth of pollen tube inside the style. 

4. Direction of pollen tube towards the micropyle of ovule. 

5. Entry of pollen tube into the synergid of embryo sac. 

6. Discharge of male gametes from the pollen tube. 

7. Fusion of male gamete with egg cell (syngany) 

8. Fusion of second male gamete with polar nuclei (triple fusion/double

The two male gametes released from a male gametophyte are involved in the fertilization. They fertilize two different components of the embryo sac. Since both the male gametes are involved in fertilization, the phenomenon is called double fertilization and is unique to angiosperms. One of the male gametes fuses with the egg nucleus (syngamy) to form , Zygote.

The second gamete migrates to the central cell where it fuses with the polar nuclei or their fusion product, the secondary nucleus and forms the primary endosperm nucleus (PEN). Since this involves the fusion of three nuclei, this phenomenon is called triple fusion. This act results in endosperm formation which forms the nutritive tissue for the embryo.

(b) I-(iii); II-(iv); III-(ii); IV-(i)

The correct option is C) Animals.

The correct option is C) Milkweed.

The correct option is D) Neem.

Sewage is a liquid containing wastes which is disposed of by households, industrial and agricultural activities in the water. It is harmful to discharge untreated sewage into rivers or seas because it can pollute the whole sources of water. Sewage contains harmful substances and disease-causing organisms.-It is therefore dangerous to release untreated sewage into water bodies.

(b) Anatropous

(d) Downward

(b) Nucellus is composed of sclerenchymatous tissue

(d) Amphitropus

After reaching the embryo sac, a pore is formed in pollen tube wall at its apex or just behind the apex. The content of the pollen tube (two male gametes, vegetative nucleus and cytoplasm) are discharged into the synergids into which pollen / tube enters. The pollen tube does not grow beyond it, in the embryo sac. The tube nucleus disorganizes.

The receptive surface of the stigma receives the pollen. If the pollen is compatible with the stigma it germinates to form a tube. This is facilitated by the stigmatic fluid in wet stigma and pellicle in dry stigma. These two also decide the incompatibility and compatibility of the pollen through recognition-rejection protein reaction between the pollen and stigma surface.

(b) ii and iv are correct

Endosperm development, embryo development, seed formation and fruit formation.

The correct option is A) Coconut.

The correct option is A) Fleshy fruits.

(a) Cactaceae – Circinotropous ovule 

(b) Leguminosae – Campylotropous ovule 

(c) Polygonaceae – Orthotropous ovule 

(d) Primulaceae. – Hemianatropous ovule

The events from pollen deposition on the stigma to the entry of pollen tube in to the ovule is called pollen – pistil interaction. It is a dynamic process which involves recognition of pollen and to promote or inhibit its germination and growth.

• Continuous self-pollination, generation after generation results in weaker progeny. 
• Chances of producing new species and varieties are meager.

The ornithophilous flowers have the following characteristic features:

1. The flowers are usually large in size. 

2. The flowers are tubular, cup shaped or um- shaped. 

3. The flowers are brightly coloured, red, scarlet, pink, orange, blue and yellow which attracts the birds. 

4. The flowers are scentless and produce nectar in large quantities. Pollen and nectar form the floral rewards for the birds visiting the flowers. 

5. The floral parts are tough and leathery to withstand the powerful impact of the visitors.

1. It supplies nutrition to the developing microspores. 

2. It contributes sporopollenin through ubisch bodies thus plays an important role in pollen wall formation. 

3. The pollenkitt material is contributed by tapetal cells and is later transferred to the pollen surface. 

4. Exine proteins responsible for ‘rejection reaction’ of the stigma are present in the cavities of the exine. These proteins are derived from tapetal cells.

Anemophily is a chance event. The liberated pollen may or may not reach the target flower and are wasted during the transmission from one flower to another. Hence enormous pollen grains are produced to assure pollination.

The characteristic features of entomophilous flowers are as follows:

1. Flowers are generally large or if small they are aggregated in dense inflorescence. 

Example: Asteraceae flowers. 

2. Flowers are brightly coloured. The adjacent parts of the flowers may also be brightly coloured to attract insect.

For example: in Poinsettia and Bougainvillea the bracts become coloured. 

3. Flowers are scented and produce nectar. 

4. Flowers in which there is no secretion of nectar, the pollen is either consumed as food or used in building up of its hive by the honeybees. Pollen and nectar are the floral rewards for the visitors. 

5. Flowers pollinated by flies and beetles produce foul odour to attract pollinators. 

6. In some flowers juicy cells are present which are pierced and the contents are sucked by the insects.

(b) j shaped curve

(d) both a and c

(a) density of population

Correct answer is (c) Hypohydrophilous

(i) Nourishment to the developing seeds and protection of the immature seeds is role of fruit formation.

(ii) When embryo(s) are formed through asexual method of reproduction without gamete formation, genetically identical plants can be produced rapidly and effectively by apomixis.

(iii) Development of fruit without the process of fertilization results in formation of seedless fruit.

(iv) As there is development of more than one embryo in the seed it increases the chances of survival of new plants.

(c) Its population growth curve is of type

(a) eurythermal

Correct answer is (a) pollination

The haploid microspores (n) and megaspores (n) are the initial cells of the male and female gametophytes.

Correct option is A) Mango

Stigmatic surface.

(a) Flowers are small and inconspicuous 

(b) Colourless 

(c) Non-scented 

(d) No nectar secretion

(i) Protandry

(ii) Gemmule formation

(iii) Tissue culture.

(iv) Micropropagation.

(v) Anatropous

1. The flowers are produced in pendulous, catkin-like or spike inflorescence. 

2. The axis of inflorescence elongates so that the flowers are brought well above the leaves. 

3. The perianth is absent or highly reduced. 

4. The flowers are small, inconspicuous, colourless, not scented, do not secrete nectar.

5. The stamens are numerous, filaments are long, exerted and versatile. 

6. Anthers produce enormous quantities of pollen grains compared to number of ovules available for pollination. They are minute, light and dry so that they can be carried to long distances by wind. 

7. In some plants anthers burst violently and release the pollen into the air. 

Example: Urtica. 

8. Stigmas are comparatively large, protruding, sometimes branched and feathery, adapted to catch the pollen grains. Generally single ovule is present. 

9. Plant produces flowers before the new leaves appear, so the pollen can be carried without hindrance of leaves.

Abiotic agents – wind, water and Biotic agents – insects, birds, bats.

Cause of annual variations in the distinct seasons: 

i. Tilt of the earth on its axis. 

ii. Rotation of earth around the sun.

The pollen grains are liberated at 2-celled stage in most angiosperms.

(d) both a and b

Jaya, Ratna.

Jaya, Ratna, are the two varieties of rice

Correct option is (a) sticky pollen with a rough surface