CBSE > Class 09 > Science | CBSE Board | Homework Help

Water, air, and soil are three natural resources that we cannot live without. The Forest Service strives to protect, maintain, and restore these valuable assets now and into the future. Water is one of the most important natural resources flowing from forests. The Forest Service manages the largest single source of water in U.S., with about one-fifth originating from 193 million acres of land which provides drinking water to 180 million people every day. Soil provides nutrients, water, oxygen and heat to natural land areas. Understanding the ability and capacity of soil to support an ecosystem plays an important role in land management decisions. Air is a third critical resource for humans, plants, animals and all other organisms within a natural area. Air must be monitored in order to control and lower pollution levels, control smoke caused by wildland fires, and to monitor air quality. The Forest Service monitors the effects of air pollution that may impair visibility, harm human health, injure trees and other plants, acidify or cause unnatural fertilization of streams and lakes, leach nutrients from soils, and degrade cultural resources, like archeological sites and historical buildings. Forest activities that can affect air quality such as prescribed burning, ski areas, and mining are also monitored to ensure compliance with air regulations for human health and to monitor possible impacts to natural resources.

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What is the fundamental unit of life .

Posted by Arya Kashyap S N 3 years, 8 months ago

CBSE > Class 09 > Science

5 answers

Sonal Tondwal 3 years, 8 months ago

Cell is the fundamental unit of life

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Palak Singhania 3 years, 8 months ago

Cell is the fundamental unit of life

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Palak Singhania 3 years, 8 months ago

Cell is the fundamental unit of light

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Sachin Kumar 3 years, 8 months ago

Cell is the fundamental unit of life

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Taranjot Kaur 3 years, 8 months ago

Cell is the fundamental unit of life

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The chapter "nature resources" will come in term end examination or not ?

Posted by Shruti Padhan 3 years, 8 months ago

CBSE > Class 09 > Science

3 answers

Nithya Sri 3 years, 7 months ago

No,

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Priyal Gupta 3 years, 8 months ago

It will only come in term

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Sarita Panda 3 years, 8 months ago

No, it will not come.

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Which is the most important formulas and question for class 9 physics and chemistry...

Posted by Sandeep Patil 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Satyaki Yadav 3 years, 8 months ago

Physics • v² = u² + 2aS • S = ut + ½at² • v = u + at • kinetic energy = ½mv² • Potential energy = mgh • F = G × Mm/d² • F = ma • W = mg

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Sumarise the rules for writing of distribution of electrons in various shells for the first eighteen elements

Posted by Sweetu Patel 3 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Diya Bj 3 years, 8 months ago

1)The maximum number of electrons that can be accommodated in a shell can be determined by the formula 2n^2.The maximum number of electrons that can be accommodated in different shells are as follows; 1st orbit or K shell 2*1^2=2,2nd orbit or L shell=2*2^2=8,3rd orbit or M shell=2*3^2=18 and so on.The maximum number of electrons that can be accommodated in the outermost shell is 8.Electrones are filled in a step-wise manner.

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Sweetu Patel 3 years, 8 months ago

The rules for writing of distribution of electrons in various shells for the first eighteen elements are: (i) The maximum number of electrons present in a shell is given by the formula-2 n2 ∵ n = orbit number i.e., 1, 2, 3 ∵ Maximum number of electrons in different shells are: K shell n = 1 2n2 => 2(1)2 = 2 L shell n = 2 2n2 => 2(2)2 = 8 M shell n = 3 2n2 => 2(3)2 = 18 N shell n = 4 2n2 => 2(4)2 = 32 (ii) The maximum number of electrons that can be accommodated in the outermost orbit is 8. (iii) Electrons are not accommodated in a given shell unless the inner shells are filled. (Shells are filled step-wise).

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Chemistry chapter 2 to is matter around us pure book back question and answer

Posted by Shivaani Duraibabu 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Diya Bj 3 years, 8 months ago

pure substances are made out of one type of particles

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If Atom is the smallest unit of non living, then please tell me how the cell is made? Explain well

Posted by Virat Jaat 3 years, 8 months ago

CBSE > Class 09 > Science

5 answers

Amardeep Singh 3 years, 8 months ago

By GOD

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Sonal Tondwal 3 years, 8 months ago

Cell is made up of chemical combination of elements and compounds and these elements are made up of atoms so every living and non living matter is made up of atom

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Priya Kumari Shriya Kumari 3 years, 8 months ago

What is evaporation

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Mahak Tiwari 3 years, 8 months ago

Cell is made up of chemical combination of elements and compounds and these elements are made up of atoms so every living and non living matter is made up of atom Ryt......

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Pruthviraj Nagaraj 3 years, 8 months ago

Cell is made up of chemical combination of elements and compounds and these elements are made up of atoms so every living and non living matter is made up of atom

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How to know physical changes and chemical changes ? ( in 5-5 points)

Posted by Virat Jaat 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Aashi Singh 3 years, 8 months ago

In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.

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Difference between chemical and physical change ?(In 5-5 points)

Posted by Virat Jaat 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Sonal Tondwal 3 years, 8 months ago

A chemical change is a permanent change. A Physical change affects only physical properties i.e. shape, size, etc. ... Some examples of physical change are freezing of water, melting of wax, boiling of water, etc. A few examples of chemical change are digestion of food, burning of coal, rusting, etc.

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How can there be an egg cell? Why is the largest cell ostrich egg?

Posted by Virat Jaat 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Satyaki Yadav 3 years, 8 months ago

Egg is an cell because it consists of an single organism inside it. Because it is very big comparing to other cells.

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What is membrane biogenis

Posted by Ishmeet Kaur 3 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Diya Bj 3 years, 8 months ago

it is the formation of cell with the help of proteins and lipids in endoplasmic reticulum mm

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Virat Jaat 3 years, 8 months ago

Membrane biogenesis, the synthesis of specific molecular components and their assembly into cellular membranes, is a critical, major activity in which cells engage throughout their existence. I hope you understand.

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What is the importance of tissue?(Answer in 5 points)

Posted by Kunal Kaushik 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Shambhavi Sagar 3 years, 8 months ago

1. Formation of tissues has brought about a division of labour in multicellular organisms. 2. Tissues become organised to from organs and organs into organ systems. 3. Workload of individual cell has decreased due to origin of tissues. 4. As a result of improved organisation and higher efficiency, multicellular organisms have higher survival.

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An iron almirah is a solid at room temperature

Posted by Manwinder Riar ☺️ 3 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Sandhya Kumari 3 years, 7 months ago

Metals have high melting point

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Kuldeep Singh 3 years, 8 months ago

Because the melting point of a an almirah is more than temperature of room

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Why ice at 283K more effective in cooling than water at same temperature ?

Posted by Manwinder Riar ☺️ 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Ritika Arya? 3 years, 8 months ago

Ice at 273 k is more effective than water at the same temperature because I said as less energy than the water at the same temperature As Ice has lost latent heat of fusion also therefore it is more effective than water at the same temperature

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The body of mass 1kg is attracted by the earth with a force equal to

Posted by Sneha Sharma 3 years, 8 months ago

CBSE > Class 09 > Science

4 answers

Manwinder Riar ☺️ 3 years, 8 months ago

The body of mass 1kg is attracted by the earth with a force equal to 9.8 N

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Tejashwi Singh 3 years, 8 months ago

9.8N

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Abhay Pratap Singh 3 years, 8 months ago

What

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Khushi Kaur 3 years, 8 months ago

9.8 N Answer. "A body of mass 1kg is attracted by the earth with a force is equal to 9.8 N .

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What are the principles of treatment ?

Posted by Hatim Paliwala 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Khushi Kaur 3 years, 8 months ago

Principles of Treatment Whenever we get sick, there are certain steps taken by us to treat the ailment. There are primarily two ways to treat a disease: 1. Reduce the effect of the disease: Medicines are provided to reduce the pain or bring down the fever. In other words, symptomatical treatment may help to reduce the impact of a disease, but it might not outright cure it. Illness like the common cold does not have a cure, hence, treating symptoms will alleviate the discomfort or illness to an extent. Bed rest is advised so that the body gets some rest. Maintaining personal hygiene also reduces the effect of the disease. However, even this does not completely kill the pathogen but only subsides the effect of the disease. Using sterilized products and eating healthy food also prevents the spread of the ailment. 2. Kill the cause of the disease: Use medicines that can kill the pathogens. Each microbe undergoes some specific biochemical life process which helps them to survive. The intake of certain drugs that block these biochemical processes can help in killing the microorganism causing the disease. Antibiotics serve the purpose. Production of anti-viral drugs is more difficult than producing anti-bacterial drugs. This is because the virus enters the body of the host and survives on its cellular machinery. Despite this, The researchers have succeeded in manufacturing the anti-viral drugs that have subsided the effects of HIV infection. Treatment prevents the progression and recurrence of the disease. It also reduces the mortality rate and improves the quality of life.

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Arenchyam is type of which tissue

Posted by Anushka Yelpale 3 years, 8 months ago

CBSE > Class 09 > Science

5 answers

Satyaki Yadav 3 years, 8 months ago

Aerenchyma is an type of simple permanent tissue. (It is an form of parenchyma tissue).

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Ritika Arya? 3 years, 8 months ago

Arenchyma is type of simple permanent tissue

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Mohit Kumar 3 years, 8 months ago

How aerencyma is a type of permanent tissue ~janvi?

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Janvi Deshwal 3 years, 8 months ago

Aerenchyma is a type of permanent tissue

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Khushi Kaur 3 years, 8 months ago

spongy tissue

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Difference between endocytosis and exocytosis

Posted by Upinderjeet Singh 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Khushi Kaur 3 years, 8 months ago

In exocytosis, a cell expels molecules and other contents that are too large to pass through the cell membrane structure. This discharge is accompanied by the fusion of the vesicular membrane and the plasma membrane. This process is carried out in three ways that separately involve the molecular constituents like endosomes, lysosomes, exosomes, neurotransmitters, etc. •In endocytosis, the body cells ingest various molecules such as proteins, polar molecules, and other substances, through their hydrophobic plasma membrane. This process is carried out by many eukaryotic cells to ingest food particles by surrounding them, and in this case, the plasma membrane is extended outwards. The basic mechanism of both the processes of exocytosis and endocytosis, is more or less the same. Vesicles are the structures used for the transportation of molecules. They are also used for storage and transportation of food. Also, many bacteria and pathogens may enter the body by this process. These structures may have a completely different internal composition as compared to that of the body cells.

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Differentiate between xylem and phloem (any 5)

Posted by Vanshika Saxena 3 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Poorvi Sharma 3 years, 8 months ago

Phloem transfer food and xylem transfer water in plants .

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Naman Singh 3 years, 8 months ago

Xylem is the complex tissue of plants, responsible for transporting water and other nutrients to the plants. Phloem is living tissue, responsible for transporting food and other organic materials. Xylem consists of dead cells (parenchyma is the only living cells present in the xylem).

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Find the number of atoms 0.5mole C of atom

Posted by Sneha Thakur 3 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Aditi Jain 3 years, 8 months ago

3.011x10²³ no. of atoms

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Keerthana N 3 years, 8 months ago

Answer. =3.01×10^23 atoms.

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Can a cell be non-living if it is possible?

Posted by Virat Jaat 3 years, 8 months ago

CBSE > Class 09 > Science

5 answers

Janvi Deshwal 3 years, 8 months ago

Yes

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Mohit Kumar 3 years, 8 months ago

Why not

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Suhani Jain 3 years, 8 months ago

No it can't

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Rimjhim Goswami 3 years, 8 months ago

Not in any condition

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Keerthana N 3 years, 8 months ago

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If Atom is the smallest unit of non living, then please tell me how the cell is made?

Posted by Virat Jaat 3 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Virat Jaat 3 years, 8 months ago

I could not understand, please and explain well

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Mohit Kumar 3 years, 8 months ago

Because a cell is made up of biological molecules and these atoms together constituent makes a atom thus in simple atoms _biological molecules_cell

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What is the acceleration of free fall?

Posted by Nitesh Rathour 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Virat Jaat 3 years, 8 months ago

An object that is moving only because of the action of gravity is said to be free falling and its motion is described by Newton's second law of motion. ... The acceleration is constant and equal to the gravitational acceleration g which is 9.8 meters per square second at sea level on the Earth.

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ut of the following, the correct diagram of the stripped muscle fibre, is the diagram labelled as: (1)

Posted by Shiv Kumar 3 years, 8 months ago

CBSE > Class 09 > Science

0 answers

ANSWER

What is atomic mass of carbon

Posted by Khushboo Kumari 3 years, 8 months ago

CBSE > Class 09 > Science

3 answers

Saniya .. 3 years, 8 months ago

12.0107 u

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Samiksha Jadhav 3 years, 8 months ago

12 u is the atomic mass of carbon .

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Khushboo Kumari 3 years, 8 months ago

12u

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Fig: Separation of NH4Cl and salt by sublimation Sea water is a mixture of salts and water which cannot be separated except by evaporation. Therefore, sea water is considered as a homogeneous mixture. But other than salts and water, sea water also contains mud, decayed plant, etc. So it is considered as a heterogeneous mixture. Therefore, sea water can be classified as homogeneous as well as heterogeneous mixture A compound is always a single substance in which two or more elements are combined chemically. A mixture is a combination of elements or compounds or both. Thus, a compound fulfils the definition of a pure substance but not a mixture. Moreover, a compound has a sharp melting or boiling point while a mixture does not have. Fog and cloud are the examples in which liquid is the dispersed phase and gas (air) is the dispersion medium. The only difference between them is that clouds are formed in the upper atmosphere while fog gets formed in the region close to earth.

Posted by Kartik Kumar 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Virat Jaat 3 years, 8 months ago

Sea water is a mixture of salts and water which cannot be separated except by evaporation. Therefore, sea water is considered homogeneous.Oct 2, 2019

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Is anyone preparing for ntse 10th

Posted by Mohit Kumar 3 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Black Bolt 3 years, 8 months ago

nope

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What is mitrochondria and function

Posted by Abdul Bashit 3 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Rimjhim Goswami 3 years, 8 months ago

Mitochondria is known as the powerhouse of the cell it is discovered by Altman and first developed by Koliker and was named as mitochondria by C Benda its function is to control the activities of the cell organelles and provide them energy.....

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. . 3 years, 8 months ago

Mitochondria is known as the power house of the cell . It provides energy to the cell for performing chemical activities.

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