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

Marestametic tissue are of three types Apical-it increases the size from top of the plant. Internodes- they are present at the part of nodes and provide strongness. Lateral-it increases the girth of the plant and provide strength.

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Why are striated muscle also known as skeletal muscles answer

Posted by Ummer Afeez 4 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Nayana Patil 4 years, 7 months ago

Because these are attached to the bones

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A.V. Techs 8D 4 years, 7 months ago

This is because Skeleton muscle are those muscle which can be work by our will ( eg.hand) and this function are also performed by the striated muscle as they are voluntry in nature.

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What are companion cells

Posted by Sanket Gorai 4 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Ummer Afeez 4 years, 7 months ago

Why are striated muscle also known as skeletal muscle

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Ummer Afeez 4 years, 7 months ago

Why are striated muscle also known as skeletal muscles

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Our flag is called

Posted by Shubham Gameplays 4 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Kyōka ( Demon Snow ) 4 years, 7 months ago

Tricolour

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Abhinav Minj 4 years, 7 months ago

National flag

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Plant is called

Posted by Shubham Gameplays 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

A.V. Techs 8D 4 years, 7 months ago

As a autotrophs which can produce their food by themselves

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Sci sample paper solution

Posted by Mayank Bansal 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Ishan Debbarma 4 years, 7 months ago

Give money

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Find the no. of aluminium ions present in 0.051g of aluminium oxide??

Posted by Jaspreet Kaur 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 4 years, 7 months ago

1 mole of aluminium oxide (Al2O3) = 2*27 + 3 * 16

= 102 g

i.e., 102 g of Al2O3 = 6.022 * 1023 molecules of Al2O3

Then, 0.051 g of Al2O3 contains =

= 3.011 * 1020 molecules of Al2O3

The number of aluminium ions (Al3+) present in one molecule of aluminium oxide is 2.

Therefore, the number of aluminium ions (Al3+) present in 3.011 * 1020 molecules (0.051 g ) of aluminium oxide (Al2O3) = 2 * 3.011 * 1020

= 6.022 * 1020

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Difference between nuclear membrane and cell membrane

Posted by Jasbir Singh 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 4 years, 7 months ago

Nuclear membrane is the double membrane surrounding nucleus in eukaryotes. Cell membrane or plasma membrane is a thin, selectively permeable membrane composed of lipids and proteins which surrounds an entire cell and regulates the flow of substances to and from the cell.

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?what would be the management criteria of cultivation so that crop yield production improvement

Posted by Ankit K.R 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 4 years, 6 months ago

Field crops are infested with a variety of pests and diseases. There are various methods by which insects and diseases controlled. The use of pesticides includes insecticides, weedicides and fungicides. These chemicals are sprayed on crop plants or used for treating seeds and soil.

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What is newton , proton,electron?

Posted by Amar Pandit Ji 4 years, 7 months ago

CBSE > Class 09 > Science

3 answers

mair****@***** 4 years, 7 months ago

Neutron:- Neutron is third sub atomic particle. It exist in nucleus along with proton. It was discovered by James Chadwick. Proton:- Proton is another sub atomic particle which exist in nucleus of an atom. It was discovered by E. Goldstein. Electron:- Electron is sub atomic particle which is discovered by J.J Thomson perform an experiment in which he found negative particles and which named an Electron.

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Kiran Yadav 4 years, 7 months ago

Electorns were discovered by JJ.thomson in 1900, protons were discovered by E.goldsteinin 1886, neutrons were discovered by James chandwik in 1932

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Meghna Thapar 4 years, 7 months ago

The proton is a positively charged particle found in the atoms of all the elements.
The negatively charged particles outside the atom are called electrons.
The neutral particles present in the nucleus along with protons are called neutrons.

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Cite an experiment to show that sound needs a material medium for its propagation

Posted by Nikhil Bikkad 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 4 years, 7 months ago

Sound Needs a Medium for Propagation:

The substance through which sound travels is called medium. The medium can be solid, liquid or a gas. Sound needs a medium for propagation means it needs a solid, liquid or gas for transmission. Sound can travel through solids, liquids and gases but it cannot travel through vacuum as it has no molecules which can vibrate and carry sound waves.

Take a ringing electric bell and place it inside an airtight glass jar. We can hear the sound from it as air is present in it and sound can travel through air.

Now, if we place the ringing bell in a glass jar containing a vacuum pump, the sound becomes fainter and fainter as air gradually removes from it. When all the air is removed from the glass jar, no sound can be heard. This shows that sound cannot travel through vacuum.

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What's valency

Posted by Bidisha Biswas 4 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Kyōka ( Demon Snow ) 4 years, 7 months ago

No. Of atoms lost or gained by an atom to get its duplet or octet complete. For e.g : Oxygen has electronic configuration as : 2,6 so it has to gain 2 electrons to get its octet complete. Therefore its valency is 2.?

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Yogita Ingle 4 years, 7 months ago

The combining capacity of the atoms to form molecules either with same or different elements is defined as valency.
Method to find valency:
If Atom has less than four electrons in its outermost shell, the valency of an atom is equal to the number of electrons present in the valence shell.
If the outer shell has more than four electrons, the valency = 8 - the number of electrons in the outer shell.
Example 1: Carbon
Electronic configuration of carbon 2, 4
Carbon has 4 electrons in its outermost shell, so the valency of Carbon is 4.

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Atoms are independently exist

Posted by Rajat Kumar 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Gourav Kumar 4 years, 7 months ago

As single atoms are very unstable so it exists only in groups.

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What is the maximum number of electrons which can be accommodated in N shell

Posted by Puran Singh 4 years, 7 months ago

CBSE > Class 09 > Science

6 answers

Abhinav Minj 4 years, 7 months ago

Fourth orbit or N shell be = 2×4×4= 32

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Mo Umair Mo Umair 4 years, 7 months ago

32 shell in N Shell

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Lucky Singh 4 years, 7 months ago

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Rajat Kumar 4 years, 7 months ago

8 electrons

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Sachin Tendulkar 4 years, 7 months ago

In shell N 32 electrons

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Sachin Tendulkar 4 years, 7 months ago

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All diagrams

Posted by Yuvasri Kamakshi 4 years, 7 months ago

CBSE > Class 09 > Science

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Different between pteridophytes and phanerogans

Posted by Owais Karigar 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 4 years, 7 months ago

Pteriodphytes	Phanerograms
Do not possess seeds	Possess seeds
These flowerless green plants comprise of ferns and their relatives	This group has well developed reproductive parts – angiosperms and gymnosperms
They are primitive forms	More advanced form
Reproductive structures are concealed hence termed as cryptogams	Well-differentiated reproductive structures
Embryo is naked	Possess embryo with stored food known as seeds

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Is there any fourth Newton law?

Posted by Arun Chauhan 4 years, 7 months ago

CBSE > Class 09 > Science

5 answers

Arpit Garg 4 years, 7 months ago

Yes it is my pocket

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Gourav Kumar 4 years, 7 months ago

Forth law is that gravity is inversely proportional to time speed.

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Ansh Anand 4 years, 7 months ago

The fourth law is not written yet

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Rajat Kumar 4 years, 7 months ago

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Harshpreet Singh 4 years, 7 months ago

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Differentiate between cryptogams and phanerogams

Posted by Mudit Maheshwari 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Mansi Pal 4 years, 7 months ago

Cryptogams do not bear seed but phanerogams bear seeds

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Difference between rough and smooth endoplasmic reticulum

Posted by Surbhi Kumari 4 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Mansi Pal 4 years, 7 months ago

Rough ER contain ribosomes for protein synthesis and SER is a site of lipid synthesis

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Wasif Raza 4 years, 7 months ago

Rough endoplasmic reticulum have hair like structure on them

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Describe modifications of stem with sutable example

Posted by Sunita Kumari 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 4 years, 6 months ago

Stems of various plants have undergone modifications to perform different functions.

Underground stems or storage stems:

Examples: Rhizomes, Corms, tubers

In ginger and banana, the underground stem is called a rhizome. The underground stem in Colocasia (arvi) is known as corm. Rhizomes and corms are underground stems, modified for the storage of food. Also, these stems help in vegetative reproduction of these plants. The tips of the underground stem in potato plants become swollen due to the accumulation of food. The potato is a tuber that helps in the storage of food and bears eyes on it. Subtended by a leaf scar, these eyes bear buds that give rise to new plants.

Supportive stems

Example: tendril

The stem in some weak plants bear thin, slender, and spirally-coiled structures called tendrils that help the plant get attached to nearby structures for support. Tendrils are found in cucumbers, melons, and other members of the family Cucurbitaceae.

Protective stems

Example: Thorns

The stem in bougainvillea and citrus plants (like lemon and orange) bear sharp, pointed structures called thorns, which provide protection to the plant from herbivores.

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What is fauna

Posted by Ansh Gupta 4 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Abhinav Minj 4 years, 7 months ago

Fauna is a animal kingdom

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Adarsh Yadav 4 years, 7 months ago

It is refer to animal

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What is the number of molecules in 0.25 mole of oxygen?

Posted by Akshita Jain 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 4 years, 6 months ago

0.25 mole of oxygen gas contain = 0.25 × 6.022 × 10^₂₃molecules.

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The nitrogen cycle is said to be a perfect cycle.Explain why?

Posted by Shashti Kapgate 4 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Sakhuja Ansh 4 years, 7 months ago

Nitrogen cycle is called a perfect cycle in the biosphere because it keeps or maintains the over all amount of nitrogen constant in atmosphere, soil and water.

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What problem did maria face as, a child while she was being trained for tennis in the u.s what sustained her

Posted by Sahil Heena Shekh 4 years, 7 months ago

CBSE > Class 09 > Science