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A typical embryo sac is 8 nucleate and 7 celled. Six of the eight nuclei become surrounded by cell wall and are organised into cells. Two of the nuclei, called polar nuclei remain in the centre of the large central cell. Three cells are grouped together at the micropylar end forming the egg apparatus. Of these, one is the female gamete and two are synergids; the synergids have special cellular thickening called filiform apparatus at the micropylar tip.

Three cells are grouped at the clealazal end; they are called antipodals. The large cell in the centre of the embryo sac is the central cell. Later 2 polar nuclei in the centre cell fused to form a depolid secondary nucleus or endosperm nucleus. Thus the embryo sac of flowering plants is 8 nucleate 7 celled at maturity. This type of embryo sac is called monosporic because it is formed from only one of the 4 megaspores.

The Porifera group animals have pores or holes in the body. They form a canal system in the body. 

Eg: Sycon, Spongilla.

The coelenterate animals are diploblastic and have a body cavity or coelom.

Eg: Hydra, Jellyfish.

In Platyhelminthes animals, the body is flat, bilaterally symmetrical, and are triploblastic.

Eg: Tapeworms, Liver flukes.

Cold blooded animals: These animals can change their body temperature according to their surroundings.

Echinoderm animals are triploblastic, Coelomate, and Spiny skinned animals. 

Eg: Echinos (Sea urchin), Antedon, Asterias (Starfish).

Arthropods are bilaterally symmetrical, segmented, and have jointed legs. 

Eg: Prawn, Housefly, Cockroach.

Animals are divided into ten groups: 

Porifera, Coelenterata, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata, Protochordata, and Vertebrate.

The term ecology was firstly used for the regions of vegetation by Haikal (1989).

(b) from Greek language

The biotic and abiotic components of an ecosystem are controlled by the ecology of that system and remain active in a certain process. Energy is required to stay active. This energy makes an ecosystem dynamic. This entire process is called energy flow. This energy flow keeps the environment naturally controlled, which results in balance in that ecosystem. There may be a crisis in this ecosystem if there is a slight change due to human or natural reasons in this process.

Continuous energy flow is required to keep any ecosystem moving smoothly. Sun is the main source of energy on Earth, but infact, very subtle amount of solar energy can only be used in the ecosystems. Just 0.02 percent of solar energy is converted into chemical energy by plants and some part can be used in other functions of the ecosystem. This micro part of solar energy is able to make an ecosystem dynamic.

The green pigment found in plants (chlorophyll) absorbs solar energy and turns it into organic particles. This process is called photosynthesis. With the help of carbon – dioxide and water, the plants work to convert solar energy into food (starch) by the process of photosynthesis. The plant develops with the help of glucose and carbohydrates and oxygen and water vapor is released into the atmosphere by the respiratory action of plants.

The accumulated chemical energy in plants is obtained by herbivores as food. Energy is lost during its transfer from plants to herbivores. After this, carnivorous organisms eat the herbivorous organisms, and even then, there is loss of energy. Thus, energy continues to flow from one nutritional level to another nutritional level. Along with this transfer of energy, it also gets lost. Thus, the quantity of energy at every consumer level decreases continuously.

According to odum, an average daily energy of 3000 k cal per square meter is obtained by insolation. Out of this, 1500 k cal energy is absorbed by plants, of which only 1% (15 k cal) is converted into chemical energy. At secondary and tertiary nutritional levels, it decreases to 1.5 k cal and 0.3 k cal respectively.

Usually, most of the energy is lost while transferring from one nutritional level to another nutritional level, but its quality increases. Energy is neither created nor destroyed, although the nature of energy can change. Thus the amount of inherent and outflow of energy in an ecosystem remains the same.

The effects of industrialization on the ecosystem are visible as given below: 

1. As a result of industrialization, environmental pollution has increased rapidly. 

2. Industrial Units are a major source of air and water pollution. On one hand, due to the poisonous gases emerging from these units, the atmosphere is constantly being polluted, and on the other hand, chemical waste water from many industrial units pollutes the rivers, underground water and sea water. 

3. Due to the pollution of rivers and underground water, the problems of drinking water in the adjoining areas of industrial cities has become acute. 

4. The emergence of chemically-polluted water in tube – wells of Pali city is a proof of this. 

5. Due to the effect of toxic gases, the ozone layer is thinning and acid rain near the industrial areas has become frequent.

6. Solid waste from industrial units is reducing the fertility of the land, which has adverse effects on the agricultural produce and productivity. 

7. Smoke emitted from industrial units is frozen in the form of a layer in the atmosphere which is proving to be a barrier in the reflection of terrestrial radiation. 

8. Industrial units emit carbon – dioxide which is responsible for global warming, and this is causing a steady increase in global temperature. 

9. The contribution of industrial units in the process of climate change has been, thereby impacting the bio – diversity and ecosystem. All these processes indirectly influence the ecosystem adversely.

PEN –successive nuclear divisions , cell wall formation occurs –endosperm.

Endosperm is usually triploid (3n) as it is formed by the fusion of three haploid nuclei, i.e., two polar nuclei of central cell which belong to the female gametophyte and the one male gametophyte.

(c) Self-pollination

DNA is the carrier of hereditary information from parent to the next generation. 

Albuminous Seed : Seed retains endosperm as it is not completely used up during embryo development. 

Eg. Wheat, maize, barley, sunflower, castor.

Non albuminous seed : Seeds do not retain endosperm as it is completely utilized during embryo development. 

Eg. Pea, grountnut.

Albuminous seeds have residual endosperm in them. For example, maize. 

Non-albuminous seeds do not have any residual endosperm. For example, pea.

Pollination and fertilization are independent of water - seed formation is more dependable,better strategies for dispersal to new habitats ,hard seed coat provides protection to embryo.

(i) Since reproductive process such as pollination and fertilisation are independent of water, seed formation is more dependable. 

(ii) Seeds have better adaptive strategies for dispersal to new habitats and help the species to colonise in other areas. 

(iii) As they have sufficient food reserves young seedlings are nourished until they are capable of photosynthesis on their own. 

(iv) The hard seed coat provides protection to the young embryo. 

(v) Being products of sexual reproduction, they generate new genetic combinations or variations.

• Non albuminous seeds have no residual endosperm as it is completely consumed during embryo development. 

Eg: Pea, ground nut.

• Albuminous seeds retain, a part of endosperm as it is not completely used up during embryo development.

Eg: Wheat, maize, barley, castor.

Watermelon, Orange and lemon because in these fruits the seeds are scattered within their edible parts and if seed are removed they become more valuable.

Significance of fruit formation : 

• The fruits protect the seeds from unfavorable climatic conditions. 
• Both fleshy and dry fruits help in the dispersal of seeds to distant places. 
• Source of many chemicals like sugars, protein, oil, organic acids, vitamins and minerals. 
• Provide nutrition to the developing seedlings. 

When the flower chosen is unisexual (female), there is no need for emasculation. Yet bagging is necessary to prevent contamination of the stigma with unwanted pollen grains.

Since apomictic seed are produced asexually so they maintain their agronomic characters. So they are used in hybrid seed industry, floriculture, horticulture.

Sharing of injection needles is not recommended to avoid the transmission of STDs like AIDS and Hepatitis from the diseased to the healthy person.

The female flower reaches the surface of water by long stalk, male flower releases the pollen grains on surface of water, pollen grains are carried by water currents, some of them reach the stigma and achieve pollination.

Sharing of needles can transmit diseases like HIV, AIDS, Hepatitis B or C from infected to noninfected individuals.

At the time of secondary response.

Vallisneria, Hydrilla

Sporopollenin is present in the exine of pollen grains. It is the most resistant organic material in nature. It provides protection to the pollen/gamete/gametophyte from unfavourable conditions or chemicals (acids, enzymes and high temperature).

Present in exine of pollen / pollen grain Sporopollenin is the most resistant organic materials. It can withstand high temperature and strong acids and alkali. it cannot be degraded by enzymes.

Correct answer is (d) Gibberellin

Correct Answer is: (C) Papaya 

Coconut flowers, Papaya, Watermelon, Cucumber, Maize, White mulberry, Musk melon, Castor bean, Marrow, Luffa, Snake gourd, Bitter gourd, Tapioca, Pumpkin, American holly, Birch, Pine, Gopher purge, Tungoil bean.

In plant A, cross-pollination leads to the occurance of mixing of characters while in Plant B self pollination and self-fertilisation results the pure character.

(c) Exine has apertures called germ pores where sporopollenin is present

(b) liquid endosperm in coconut

Polyembryony.

Pseudo force is an apparent force which has no origin. It arises due to the non-inertial nature of the frame considered.

There are two types of Friction: 

(1) Static Friction:

Static friction is the force which opposes the initiation of motion of an object on the surface. The magnitude of static frictional force f lies between

0 ≤ f_s ≤ μ_sN

where, µ_s – coefficient of static friction 

N – Normal force

(2) Kinetic friction:

The frictional force exerted by the surface when an object slides is called as kinetic friction. Also called as sliding friction or dynamic friction,

f_k – µ_k N

where µ_k – the coefficient of kinetic friction 

N – Normal force exerted by the surface on the object

Methods to reduce friction: 

Friction can be reduced

• By using lubricants 
• By using Ball bearings 
• By polishing By streamlining 

The correct answer is A) Node.

• The part of the plant that presents above the surface of soil is the stem. 
• The part of the plant that presents below the soil surface is the stem. 
• Stem possess nodes, inter nodes and leaves etc. whereas root cannot have these.

The correct answer is B) Transpiration.

The correct answer is A) Root.

Petiole connects leaf lamina with the stem.

The stem of a plant, 

• supports the branches, leaves, flowers and fruits. 
• transports water and minerals from roots to upper aerial parts of the plant. 
• transports food from leaves to other parts. 
• in some plants, it stores the food so that they are known as the modified stem. 

Ex. Potato, turmeric, ginger, garlic and sugarcane.

Step 1: When sodium chloride reacts with conc. H₂SO₄, it forms hydrogen chloride (HCl) and sodium sulphate (Na₂SO₄).

The reaction that takes place is: 

2NaCl + conc. H₂SO₄→ 2HCl + Na₂SO₄ 

Thus, A is concentrated H₂SO₄ 

Step 2: When hydrogen chloride reacts with iron metal (Fe), it forms iron (II) chloride (FeCl₂) and hydrogen gas (H₂).

The reaction that takes place is: 

Fe + HCl → FeCl₂ + H₂ 

Thus, B is Fe. 

Step 3: When hydrogen chloride reacts with ammonia (NH₃), it forms ammonium chloride (NH₄Cl). 

The reaction that takes place is: 

NH₃ + HCl → NH₄Cl 

Thus, C is ammonia (NH₃). 

Step 4: When hydrogen chloride reacts with lead nitrate [Pb(NO₃)₂], it forms lead chloride (PbCl₂) and nitric acid (HNO₃) .

The reaction that takes place is:

Pb(NO₃)₂ + HCl → PbCl₂ + HNO₃ 

Thus, D is lead nitrate [Pb(NO₃)₂]