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Ask QuestionPosted by Harshita Bansal❤️ 5 years ago (10189189)
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Chinmay Behera 5 years ago (10058242)
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Yogita Ingle 5 years ago (2577571)
Availability of adequate water for irrigation has changed the cropping pattern of various regions. Many farmers because of the increased availability of water have switched over to the cultivation of water intensive commercial crops such as jute, cotton and tea, rather than food grains such as bajra, wheat and ragi.
The changed cropping pattern has affected the ecological balance of some of the regions as increased irrigation has led to salinity of soil. This has reduced the fertility of the soil.
Diksha Laniya🐥 5 years ago (10085318)
Posted by Ishant Raj 5 years ago (10202301)
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Ashmita Das 5 years ago (10150611)
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Yogita Ingle 5 years ago (2577571)
मनुष्यता’ कविता के माध्यम से कवि यह संदेश देना चाहते हैं कि प्रत्येक मनुष्य को मानवीय गुणों का पालन करते हुए परहित में जीवनयापन करना चाहिए। उन्नति की राह में एक साथ आगे बढ़ना चाहिए। वह चाहता है कि प्रत्येक व्यक्ति अपने व अपनों के हितों से पहले दूसरों के हितों की चिंता करे। अपने बल, बुद्धि, समृद्धि का प्रयोग सबके उत्थान के लिए करे और प्राणीमात्र से प्रेम करें।
Posted by Mark Debbarma 4 years, 8 months ago (10185507)
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Sia ? 4 years, 8 months ago (6945213)
A query works the same way. It gives meaning to the code used in any query language.
Posted by Gourav Shekhawat 4 years, 4 months ago (9809647)
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Posted by Ashish Kashyap 5 years ago (10202153)
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Aaliyah _ 5 years ago (10201963)
Yogita Ingle 5 years ago (2577571)
The flying of aeroplane is due to application of bernaullis theorem
the wings of the aeroplane are made in such a way that the pressure of the air above the wings decreases and due to which the plane lifts up
Posted by P R 5 years ago (9622773)
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Posted by P R 5 years ago (9622773)
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Gaurav Seth 5 years ago (2898529)
9 Science notes Chapter 6 Tissues
Download CBSE class 9th revision notes for Chapter 6 Tissues in PDF format for free. Download revision notes for Tissues class 9 Notes and score high in exams. These are the Tissues class 9 Notes prepared by team of expert teachers. The revision notes help you revise the whole chapter in minutes. Revising notes in exam days is on of the best tips recommended by teachers during exam days.
<a href="https://mycbseguide.com/downloads/cbse-class-09-science/1218/cbse-revision-notes/7/">Download Revision Notes as PDF</a>
Posted by Swati Mishra 5 years ago (10198671)
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Gaurav Seth 5 years ago (2898529)
Moving Air is called wind. And energy produced from Wind is called Wind Energy. Wind is caused due to unequal heating of land and water bodies by the sun. This unequal heating generates air movement and causes winds to blow. This kinetic energy of wind is used to generate wind energy from a Windmill.
Posted by Manya Aggarwal 5 years ago (10197439)
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Diksha Laniya🐥 5 years ago (10085318)
Posted by Sawan Sharma 5 years ago (10160858)
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Yogita Ingle 5 years ago (2577571)
Justify alignment: This alignment joins the text with both the left and right margins, and stretches the text if needed. This alignment is used mostly for writing circulars, notices etc....
Posted by P R 5 years ago (9622773)
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Gaurav Seth 5 years ago (2898529)
|
Features |
Parenchyma |
Collenchyma |
Sclerenchyma |
| Cell shape | Isodiametric cells which are oval, spherical or polygonal in shape. | Circular, oval or polyhedral. | Variable in shape. Fibres and sclereids. |
| Cell wall | Thin cellulosic cell wall. | Uneven thickening on their cell wall. | Lignified secondary cell wall present. |
| Cytoplasm | Abundant | Present | Absent |
| Nucleus | Present (Living tissue) | Present (Living tissue) | Absent (Dead tissue) |
| Vacuoles | Large vacuole | Vacuolated | Absent |
| Intercellular spaces | Present | Absent | Absent |
| Occurrence | Basically packing tissue, all soft part of plant-pith, cortex, medullary rays. | Dicot stems, petiole and beneath the epidermis. Absent in monocot and roots. | Dicot hypodermis, bundle sheath, pericycl, seed, pulp of fruits. |
| Functions | Food storage, photosynthesis. | Provide tensile strength, mechanical support, photosynthesis. | Protection from stress and strain, mechanical strength. |
Gaurav Seth 5 years ago (2898529)
Tissue
A group of cells that are specialized to perform a particular function forms a tissue.
Tissues are mainly classified into two types:
1. Plant Tissues 2. Animal Tissues
1. Plant tissues
- Plants do not move, i.e., they are stationary.
- Most of the tissues they have are supportive, which provides them with structural strength.
- Most of these tissues are dead, as they can provide better mechanical strength than the live ones, and need less maintenance.
- Some of the plant tissues keep on dividing throughout the plant life. These tissues are localised in certain regions.
Types of Plant Tissues:
Based on the dividing capacity of the tissues, various plant tissues can be classified as growing or meristematic tissue and permanent tissue which have further sub-divisions as explained below:
Yogita Ingle 5 years ago (2577571)
Tissues
Group of cells having a common origin and similar function are termed as tissues.
A. Plant tissues: On the basis of the dividing capacity, plant tissues are of two types:
- Meristematic tissues
- Permanent tissues
1. Meristematic tissues: Consist of actively-dividing cells. Meristematic tissues are of three types:
- Apical meristem: Present at the growing tips of stems and roots. Important function: To increase the length of stems and roots.
- Intercalary meristem: Present at the base of leaves or internodes. Important function: For the longitudinal growth of plants.
- Lateral meristem: Present on the lateral sides of the stems and roots. Important function: To increase the thickness of stems and roots.
2. Permanent tissues: Formed from meristematic tissues, the cells in the tissue loose the ability to divider Permanent tissues are divided into two categories:
- Simple permanent tissue: Consist of only one type of cells.
Types of simple permanent tissues:
-
- Parenchyma: Composed of unspecialised living cells with relatively thin cell walls, intercellular space, present in soft parts of the plant. Their main function is storage.
- Collenchyma: Composed of living and elongated cells with cell walls irregularly thickened at the comers. No intercellular space. It provides mechanical support and elasticity to plant. It helps in bending of leaves and stems.
- Sclerenchyma: Composed of long, narrow, and thick-walled cells. This tissue is made up of dead cells and there are no intercellular spaces. Sclerenchyma cells are dead, present in seeds, nuts, the husk of a coconut, fibres of jute etc.
- Complex permanent tissue: Made up of more than one type of cells (Conducting tissues.)
Types of complex permanent tissues:- Xylem: Conducts water and minerals from the roots to the different parts of the plant.
Composed of four different types of cells—tracheids, vessels, xylem parenchyma and xylem fibres. - Phloem: Conducts food material from the leaves to the different parts of the plant.
Composed of four different types of cells—sieve tubes, companion cells, phloem parenchyma and phloem fibres.
Protective tissue: It is made of a single layer of cells. E.g., epidermis. The epidermis of the leaf bears stomata.
- Xylem: Conducts water and minerals from the roots to the different parts of the plant.
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Ashna Gurjar 5 years ago (8467338)
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Yogita Ingle 5 years ago (2577571)
Sadao’s education was his father’s chief concern. For this reason he had sent Sadao to America to learn all that could be learned about surgery and medicine. Before his death he had seen Sadao become famous not only as a surgeon but as a scientist.
Gaurav Seth 5 years ago (2898529)
Sadao’s father was an ambitious person. He wanted to make his son only a famous doctor. Therefore, he sent Sadao to America to attain higher education. Sadao mastered the art of healing wounds. Sadao came to his father’s expectations when he became a successful surgeon and a famous scientist.
Posted by Lalit Kumar 5 years ago (9616175)
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Diksha Laniya🐥 5 years ago (10085318)
Posted by Swati Mishra 5 years ago (10198671)
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Gaurav Seth 5 years ago (2898529)
- The energy obtained from the sun is called solar energy
- Sun's heat which falls on the earth can be harnessed for various heating and lighting purposes.
- Most of the sun's heat is absorbed is the atmosphere.
- Only a very small portion reaches the earth and it is this energy that can be harnessed for energy purposes.
- A black surface absorbs more heat than a white surface.
- This property is used in Solar cookers, Solar water heaters and Solar cells.
Posted by Diksha Laniya🐥 5 years ago (10085318)
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Anshika Rawat 5 years ago (10302300)
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