CBSE > Class 08 > Science | CBSE Board | Homework Help

Nitrogen: Nitrogen is the largest component of air. Nitrogen makes up 79% of air around us. Nitrogen is used by plants to make protein. Plants cannot take nitrogen directly from the air. Some nitrogen fixing bacteria live in soil. They help in nitrogen fixation in soil. Thus, plants are able to take nitrogenous compounds from the soil.

Oxygen: Oxygen is the second largest component of air. Oxygen makes up 21% of the air around us. Oxygen is used by living beings for respiration. After respiration, the living beings produce carbon dioxide.

Carbon dioxide: The remaining 1% of air is composed of carbon dioxide, many other gases, water vapour and dust particles. Carbon dioxide is also important for living beings. Plant need carbon dioxide to make food during photosynthesis. During photosynthesis, plants take in carbon dioxide and release oxygen. Thus, green plants help in maintaining the balance of carbon dioxide and oxygen in atmosphere.

2Thank You

ANSWER

The angle between incident ray and reflected ray is 90 degree . What is the value of angle of incidence and angle of reflection ?

Posted by Nirmal Singh Bisht 6 years ago

CBSE > Class 08 > Science

1 answers

Ritesh Yadav 6 years ago

90°

0Thank You

ANSWER

What is reproduct

Posted by Mamatha D Mamatha D 6 years ago

CBSE > Class 08 > Science

1 answers

Bikash Ranjan Sahoo 6 years ago

Making an indivisual by their parents

1Thank You

ANSWER

The eggs of frog do not have any shell still they are protected in water. Why?

Posted by Shikha Kashver 6 years ago

CBSE > Class 08 > Science

1 answers

Shikha Kashver 6 years ago

Because they have a jelly coating above them which prevent them from bursting when striked to external resource.

1Thank You

ANSWER

What is virtual image?

Posted by Anna Gurkahad A 6 years ago

CBSE > Class 08 > Science

1 answers

Yogita Ingle 6 years ago

The image produced when the light arising from an object appears to strike a certain point
It cannot be captured on a screen as it is the imaginary intersection of ray of light
The images are erect

0Thank You

ANSWER

Who discovered the term cell

Posted by Xyz Abc 6 years ago

CBSE > Class 08 > Science

6 answers

Foram Mandali 5 years, 11 months ago

Robert Hooke, he observed dead cells under a microscope in 1665.

0Thank You

Ritesh Yadav 6 years ago

Robert hooke

0Thank You

Samridhi Sinha 6 years ago

Robert hooke in 1665

0Thank You

Gurleen Kaur 6 years ago

Robert hooke

0Thank You

Aryan Rathour 6 years ago

Robert hook

0Thank You

Yogita Ingle 6 years ago

Robert Hook discovered cells in 1665. When he observed thin slices of cork (part of bark of a tree) under a self-designed microscope, he noticed that there are many partitioned boxes or compartments like a honeycomb. Each box was separated from the other by a wall. Hook coined the term “cell” for each box.

0Thank You

ANSWER

Define water pollution in short?

Posted by Rama Dey 6 years ago

CBSE > Class 08 > Science

5 answers

Ritesh Yadav 6 years ago

When a poisonous substance mix in a water it make a polluted water so it is called water pollution

0Thank You

Aditi Kumari 6 years ago

The contamination or mixing of waste materials or animal excreta and harmful chemicals in the water is known as water pollution

0Thank You

Rekha Sharma 6 years ago

How do natural gas occur in nature

1Thank You

Yogita Ingle 6 years ago

Water pollution can be defined as the contamination of water bodies. Water pollution is caused when water bodies such as rivers, lakes, oceans, groundwater, and aquifers get contaminated with industrial and agricultural effluents.

When water gets polluted, it adversely affects all lifeforms that directly or indirectly depend on this source. The effects of water contamination can be felt for years to come.

2Thank You

@Purbita# ******* 6 years ago

The contamination of water of river,lakes,and ponds etc.with unwanted and harmful substances is called waterq pollution.☺

4Thank You

ANSWER

Why is chromium metal used for electroplating car parts , bath taps etc.??

Posted by @Purbita# ******* 6 years ago

CBSE > Class 08 > Science

3 answers

Utkarsh Shukla 6 years ago

Because it is corrosion resistense

1Thank You

Rekha Sharma 6 years ago

How do natural gas occur in nature

0Thank You

Yogita Ingle 6 years ago

Electroplating is done to prevent rusting of metals and to give them an attractive and shiny look. Chromium is used to electroplate car parts, bath taps, kitchen gas, etc. burners to give them a shiny look. Chromium is a bright , shiny metal.

1Thank You

ANSWER

What is the symbol of Graphit

Posted by Spandan Chaudhari 6 years ago

CBSE > Class 08 > Science

3 answers

Revathi Sivaraman 6 years ago

0Thank You

Sujal Kumar 6 years ago

0Thank You

Akshat Bahuguna 6 years ago

1Thank You

ANSWER

Internal structure of human ear simple diagram

Posted by Neetu Neetu 6 years ago

CBSE > Class 08 > Science

2 answers

Utkarsh Shukla 6 years ago

Everything can't be simple ??

0Thank You

Kiran Pal Rathi 6 years ago

???????

3Thank You

ANSWER

What is silk

Posted by Riju Roy 6 years ago

CBSE > Class 08 > Science

3 answers

Ritesh Yadav 6 years ago

Silk is a natural fibre it is made up of thread like filament of fibre 8 obtained from coocon by various process

0Thank You

X X 6 years ago

Silk is a natural fibre which is obtained from silk worm

0Thank You

Yogita Ingle 6 years ago

Silk is a natural protein fibre which can be used as a textile fibre. It is one of the important animal fibres obtained from silkworm.

0Thank You

ANSWER

Is rayon also called synthetic silk

Posted by Laden Bhutia 6 years ago

CBSE > Class 08 > Science

4 answers

Ritesh Yadav 6 years ago

Yes Rayon is a synthetic fibre because it obtained from chemically

0Thank You

Utkarsh Shukla 6 years ago

Yes because it is proceeded after using chemicals, but it's raw material is wood pulp

0Thank You

X X 6 years ago

Yes

0Thank You

Laden Bhutia 6 years ago

Yes

0Thank You

ANSWER

,Convert 300k to c

Posted by Gurlal Singh 6 years ago

CBSE > Class 08 > Science

1 answers

Utkarsh Shukla 6 years ago

27c

1Thank You

ANSWER

Pollination

Posted by Bahuguna Sandeep 6 years ago

CBSE > Class 08 > Science

3 answers

Ritesh Yadav 6 years ago

the transfer of pollen grain from the anther of one plant to the stigma of another plant is called pollination there are two types of pollination 1 self pollination 2 cross pollination

0Thank You

Dev Sehrawat 6 years ago

The transfer of pollen grains from the anther to the stigma of a flower is known as pollination.

0Thank You

Meghna Thapar 6 years ago

The transfer of pollen grains from the anther of a stamen to the stigma of a carpel is called pollination.

0Thank You

ANSWER

Water is not used to control fire involving electrical equipments why

Posted by Naidu Diptirani 6 years ago

CBSE > Class 08 > Science

3 answers

Dev Sehrawat 6 years ago

Because it is a good conductor of electricity. So when we will use water to control fire then we might get shock.

0Thank You

Yajat Kohli 6 years ago

Yes

0Thank You

Naidu Diptirani 6 years ago

water is not used to control the fire involving electric equipment because it is a good conductor of electricity electricity resulting in electric shocks to the user

2Thank You

ANSWER

Use and disadvantages of friction with examples

Posted by Anshu Man Naik 6 years ago

CBSE > Class 08 > Science

1 answers

Meghna Thapar 6 years ago

Advantages of friction:

We are able to walk on ground because friction between the sole of our shoes and ground prevents us from slipping over the ground.
Friction between tyres of a car and the road enables a car to move forward on road without skidding.
The brakes of a car or a bicycle work by friction.
We are able to write and make drawings on paper because there is friction between the tip of pencil and paper.
We can hold a glass tumbler in our hands because of friction between the glass tumbler and our hands.
We are able to fix nails in a wall due to friction.