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When was vaccum cleaner invented??

Posted by Mahak Mehra 5 years ago

CBSE > Class 08 > Science

1 answers

Meghna Thapar 5 years ago

The original vacuum cleaner required a number of improvements before becoming the household staple it is today. Hubert Cecil Booth was born to suck. On this day in 1901, the inventor patented the vacuum in the U.K.–or an early version of it, at least. In 1901 powered vacuum cleaners using suction were invented independently by British engineer Hubert Cecil Booth and American inventor David T. Kenney. Booth also may have coined the word "vacuum cleaner".

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What is crops known for examples

Posted by Manreet Kaur Gill 5 years ago

CBSE > Class 08 > Science

3 answers

Pavitra Rajpurohit 5 years ago

Daily uses.To fulfill the needs

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Raavi Tyaja .N 5 years ago

Daily uses such as food, baga

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Rohit Kanojiya 5 years ago

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What is fossils fules

Posted by Darsh Darsh 5 years ago

CBSE > Class 08 > Science

2 answers

Vikash Kumar 5 years ago

The fuels obtain from remains of plants and animal buried under the earth over million s of years.

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Yogita Ingle 5 years ago

Fossil Fuels

Fossil fuel refers to the deposits of organic materials, formulated from dead plants and animals under several thousand feet of silt. With the passage of time they decayed and have been converted to Petroleum or crude oil, coal, natural gas, on exposure to high heat and pressure deep inside the earth’s crust over millions of years and hence they are also known as non-renewable energy source.

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Explain the process of formation of petroleum?

Posted by Akanshi Sharma 5 years ago

CBSE > Class 08 > Science

3 answers

Yogita Ingle 5 years ago

Petroleum was formed from dead organisms that got buried in the sea millions of years ago. These dead bodies got covered with layers of sand and clay. Lack of air, high temperature, and high pressure transformed these dead organisms into petroleum and natural gas.

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Hinal ... 5 years ago

The fossil fuel petroleum is form when a large quantity of dead organims are buried underneath sedimentary rocks and subjected to intense heat and pressure. Petroleum is mostly recovered by oil drilling..........

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Akanshi Sharma 5 years ago

I want ans

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Mo(oh)=mgo ??

Posted by Soham Bhayani 5 years ago

CBSE > Class 08 > Science

1 answers

Jogender Panchal 5 years ago

What is since

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Explain why some fibers are called synthetic? ( Please short and clear give me answer) ? ??

Posted by Hinal ... 5 years ago

CBSE > Class 08 > Science

3 answers

Deepakshi Dua 5 years ago

Some fibres are called synthetic because they are man-made and are formed with the help of chemicals.

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Mahak Mehra 5 years ago

They called so because they are made by humans in laboratories by combining various chemicals

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Kriti Kotiyal 5 years ago

Some fibres are called synthetic fibres because they are made by humans in laboratories rather than they are natural.

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The smallest structural and functional unit of an organism, which is typically microscopic and consists of cytoplasm and a nucleus enclosed in a membrane. All organisms are made of smaller parts called organs. Organs are made of still smaller parts. The smallest living part of an organism is a ‘cell’. Cells were first observed in cork by Robert Hooke in 1665. Cells exhibit variety of shapes and sizes. Number of cells also varies from organism to organism. Some cells are big enough to be seen with the unaided eye. Hen’s egg is an example. Some organisms are single-celled, while others contain large number of cells. The single cell of unicellular organisms performs all the basic functions performed by a variety of cells in multi cellular organisms. The cell has three main parts, (i) the cell membrane, (ii) cytoplasm which contains smaller components called organelles, and (iii) the nucleus. Cell membrane: The basic component of a cell. The cytoplasm and nucleus are enclosed within cell membrane. There is an outer thick layer in cells of plants called cell wall. Cytoplasm: The jelly-like substance present between the cell membrane and the nucleus. Various organelles present in the cytoplasm are: (i) Mitochondria (ii) Plastids (present only in plant cell) (iii) Endoplasmic reticulum (ER) (iv) Ribosome (v) Lysosomes (vi) Vacuole (vii) Golgi body (viii) Centrosome (present only in animal cell). Nucleus: Nucleus is separated from cytoplasm by a nuclear membrane. It is generally spherical in the centre of the cell. Nuclear membrane: Nucleus is separated from the cytoplasm by a membrane called the nuclear membrane. Nucleolus: Nucleus contains a still smaller round body known as nucleolus. Chromosomes: Nucleus contains thread-like structures called chromosomes. These carry genes and help in inheritance or transfer of character from the parents to the off springs Cells without well organised nucleus, i.e. lacking nuclear membrane, are called prokaryotic cells. Plant cells differ from animal cells in having an additional layer around the cell membrane termed cell wall. Coloured bodies called plastids are found in the plant cells only. Green plastids containing chlorophyll are called chloroplasts. Plant cell has a big central vacuole unlike a number of small vacuoles in animal cells. Size of cells: The size may be as small as a millionths of a metre or may be as large as a few centimetres. Size of the cells has no relation with the size of the body of the animal or plant. It is related to its function.

Posted by Aditya Dwivedi Dwivedi 5 years ago

CBSE > Class 08 > Science

1 answers

Hinal ... 5 years ago

Thanks

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Can anyone send me a short note about synthetic fibres and plastics plz

Posted by Janki Mehta ?? 5 years ago

CBSE > Class 08 > Science

4 answers

Rathod Sahil Jnvsk Roll.No–31 5 years ago

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Bhavya Punia 5 years ago

synthetic fibre, as well as plastic, is made up of a chain of small units (called Monomers) which combine to form polymers. Monomers: A monomer is a single molecule that can bond with other identical molecules to form polymers through a process called Polymerization. Polymers: Polymer is a Greek word in which 'poly' means 'many' and 'mer' means units. Hence, polymers are large molecule made up of several molecules (or monomers) linked together.

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Mahak Mehra 5 years ago

Synthetic fibre is man made fibre or we can say artificial fibre and it is made by the composition of various chemicals

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Shreya Kumbhar 5 years ago

Synthetic fibre means man-made fibre that's why it is called synthetic fiber these are joined by the small chain like parts called polymer. Plastics is versatile,hygienic,lightweight,flexible and highly durable.it account large scale use of packaging application eg.container, bottles.

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algae has green colour due to chlorophyll .what is the reason there are red algae and blue green algae an brown algae

Posted by Venkat Sairaghav Vasudevan 5 years ago

CBSE > Class 08 > Science

2 answers

Veda Rane 5 years ago

•An algae is a unicellular cell. •We know that cell contains- ~cytoplasm(organelles) ~ nucleus (nucleolus, chromosome,genes) ~vacuole ~plastid ~membrane.. •here we have observed that many things are present in an cell in which the *plastid* is a product which produces colour to any thing... We conclude that any colour algae has its colour because of the plastid.

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Gaurav Seth 5 years ago

Red Algae

The pigments phycocyanin and phycoerythrin are responsible for the characteristic red colouration of the algae. Other pigments that provide green colouration (such as chlorophyll a) are present. However, they lack chlorophyll b or beta-carotene.

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What is polymer? Anyone please give me answer

Posted by Hinal ... 5 years ago

CBSE > Class 08 > Science

2 answers

Hinal ... 5 years ago

Thank you Gaurav

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Gaurav Seth 5 years ago

A polymer is a very big molecule formed by the combination of a large number of small molecules.

Polymers are of 2 types:

1)Natural polymers:Cotton,wool,silk.

Cotton fibre is made of a natural polymer called cellulose.

Cellulose is a polymer which is made up of a large number of small glucose molecules joined one after the other.The walls of all plants cells are made up of cellulose.

2)Synthetic polymer:Nylon,polyester,acrylic,poly ethene,polyvinylchloride,bakelite,melamine.

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What is a sexual reproduction?

Posted by Hinal ... 5 years ago

CBSE > Class 08 > Science

0 answers

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Uses of metals and non metals please mujhe koi iski definition bhej sakta hai

Posted by Hinal ... 5 years ago

CBSE > Class 08 > Science

1 answers

Yogita Ingle 5 years ago

Uses of metals:

Copper and aluminium are used to make wires for carrying electric currents.
Zinc is used for galvanising iron to protect iron from rusting.
Silver, gold and platinum are used make jewellery.
Iron, copper and aluminium metals are used to make utensils for cooking and for manufacturing machines parts.
Mercury is used in thermometer.
Lead is mainly used for making electrodes for automobile batteries and for making alloys.

Uses of non-metals:

Hydrogen is used in manufacture of ammonia, industrial chemicals.
Liquid nitrogen is used in refrigerant, in storing human organs at low temperature.
Sulphur is used in manufacture of sulphuric acid, sulphur dioxide gas, sulphur drugs etc.
Sulphur is used for vulcanisation of rubber and making gunpowder.
Phosphorus is used in the manufacture of fertilisers.
Silicon is used for making semiconductors foe which microchips ar

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Posted by Rachit Singh 5 years ago

CBSE > Class 08 > Science

1 answers

Hinal ... 5 years ago

Hii Rachit

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Metal are gold ,silver, platinum

Posted by Khushi Lohani 5 years ago

CBSE > Class 08 > Science

3 answers

Hinal ... 5 years ago

Nice Explanation ?Anand

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Rachit Singh 5 years ago

Uyyi

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Anand Kumar 5 years ago

Gold,silver, platinum, palladium _are precious metals , meaning they are rare metallic chemical element of the high economic value shiny hard strong with high melting point they form alloys (mixture) with other metal and this makes them deal for jewelry

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Is polyster hard or soft

Posted by Annirudh Pandita 5 years ago

CBSE > Class 08 > Science

1 answers

Priyesh Saxena 5 years ago

Polyester is cloth like, feels smooth and is wrinkle-free .

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Define agricultural practice

Posted by Smita Sethi 5 years ago

CBSE > Class 08 > Science

2 answers

Arya Sharma 5 years ago

Agricultural practice means basically a collection of principles to apply for farm production processes in order to get better agricultural product .

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Saloni Kishor 5 years ago

Growing crops on a field for obtaining food is called agriculture

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List the various types of irritation

Posted by Dhoni S 5 years ago

CBSE > Class 08 > Science

1 answers

Palak Arora 5 years ago

There are two types of irrigation 1)Traditional methods 2)Modern methods

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Name the three synthetic fibres?

Posted by Aditya Sonara Jnv Rajkot 5 years ago

CBSE > Class 08 > Science

5 answers

Routhu Anjana Sri 5 years ago

Nylon , rayon , polyester , plastic , acrylic .

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Dhoni S 5 years ago

Rayon, nylon, acrylic

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Saloni Kishor 5 years ago

Nylon Rayon Polyeter

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Hansika Singaria 5 years ago

Nylon, polyester, rayon, acrylic

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Akshaya Reddy Reddygaari G8 5 years ago

Rayon , Nylon , Polyester , Acrylic

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What is human beings

Posted by Kunal Kumar 5 years ago

CBSE > Class 08 > Science

3 answers

Niranjana.P. A P. A 5 years ago

Human beings are people who have knowledge and skill to improve level of technology and they can also perform various activities.They are persons who have the ability to think.

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Kunal Kumar 5 years ago

Answer Er

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Aditya Sonara Jnv Rajkot 5 years ago

Man

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Which types of becteria fix nitrogen cycle

Posted by Aditya Sonara Jnv Rajkot 5 years ago

CBSE > Class 08 > Science

5 answers

Tushar Solanki 5 years ago

Rhizobium is the type of bacteria that fix in soil

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Shreya Kumbhar 5 years ago

Rizobium

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Niranjana.P. A P. A 5 years ago

Rhizobium

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Aditya Sonara Jnv Rajkot 5 years ago

Tnx

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Saloni Kishor 5 years ago

Rhizobium bacteria fix nitrogen in soil And denitrifing bacteria helf in sending nitrogen back to air

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Describe how non green plant obtain their food?

Posted by Komal Kumari 5 years ago

CBSE > Class 08 > Science

4 answers

Kriti Kotiyal 5 years ago

Non green plant such as parasites obtain their food by depriving nutrients of host plants, and fungi by saprotrophic nutrition.

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Niranjana.P. A P. A 5 years ago

With the help of other green plants.

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Routhu Anjana Sri 5 years ago

On other plants around them

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Aditya Sonara Jnv Rajkot 5 years ago

On rizobium becteria

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The energy used up in overcoming friction, gets converted mainly into -

Posted by Tanushree Mukherjee 5 years ago

CBSE > Class 08 > Science

1 answers

Priyesh Saxena 5 years ago

Heat

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What is the difference between sliding and rolling friction

Posted by Preksha Rani Epari 5 years ago

CBSE > Class 08 > Science

2 answers

Anand Kumar 5 years ago

Sliding _ the fraction that acts between an object and a surface when the object is sliding over that surface•rolling friction_ the force of fraction resisting the (rolling) motion when a body rolls on a surface

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Good Student 5 years ago

Sliding friction means, one object sild on another object example ice slide floor and rolling friction also object roll to other object. Example vehicle wheel roll on road.

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What exactly mean of Microrgansim

Posted by Meet Vasoya 5 years ago

CBSE > Class 08 > Science

5 answers

Aadya Vats 5 years ago

Living organism that are around us but cannot seen by unaided eyes.This is called microrganism.Microrganism are also as microbes

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Hardik Goyal 5 years ago

Yes

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Vaishnavi Singh 5 years ago

The living organisms ,that are invisible to the naked eye but visible under microscope,are called microorganisms.

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Ishwari 💜💜 Lanjewar 5 years ago

The living organisms which we cannot see them by our unaided eyes. It can only seen under Microscope.

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Meet Vasoya 5 years ago

Sjdjddisns

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If RBC does not have nucleus then why they are called as eukaryotes

Posted by Piyush Raj Albela 5 years ago

CBSE > Class 08 > Science

5 answers

Aditya Sonara Jnv Rajkot 5 years ago

Your Q.is wrong! Sorry to say that ..but every living and non-living thing has a cell in it and every cell contains a nucleus.so, indirectly RBCs also contains a nucleus.

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Ishwari 💜💜 Lanjewar 5 years ago

Your question is wrong, because in Ukaryotic Cell and Nucleus is present

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Veda Rane 5 years ago

Your Q.is wrong! Sorry to say that ..but every living and non-living thing has a cell in it and every cell contains a nucleus.so, indirectly RBCs also contains a nucleus.

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Meet Vasoya 5 years ago

Questiom =Question

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Meet Vasoya 5 years ago

I do not understand your questiom

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How to solve a chemical equation

Posted by Sheetal Kumari 5 years ago

CBSE > Class 08 > Science

1 answers

Mohd Bashir 5 years ago

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Name and describe the different types of coal.

Posted by Koninika Pandit 5 years ago

CBSE > Class 08 > Science

3 answers

Anand Kumar 5 years ago

Coal is readily combustion black rock or a brownish black sedimentary rock•and after how many types of coal? There are four types of coal are -peats,lignite, bituminous coal, anthracite

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Niranjana.P. A P. A 5 years ago

Different types of things obtained from coal is coal tar, coke, and coal gas.

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Dhoni S 5 years ago

Coal is coal so it's is called coal

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Give exemple which indicate that nylon fibres are very strong

Posted by Muskan Bandhakar 5 years ago

CBSE > Class 08 > Science