Sometimes, manure is added to the soil before tilling because:

1

(a)

less manure is used

(b)

it helps in proper mixing of manure with soil

(c)

It saves labour and time

(d)

none of above.

The most reactive metal is

1

(a)

gold

(b)

copper

(c)

potassium

(d)

zinc

Various materials which are obtained from nature are called natural resources. Which of the following is not a natural resource?

1

(a)

Minerals

(b)

Water

(c)

Soil

(d)

Plastic

Identify the statement which is true for cells:

1

(a)

Cells can be easily seen with naked eyes.

(b)

Insect's egg is not a cell

(c)

A single cell can perform all the functions in a unicellular organism

(d)

The size and shape of cells is uniform in multicellular organism

Which endocrine gland is called 'Master gland'?

1

(a)

Adrenal

(b)

Pancreas

(c)

Pituitary

(d)

Thyroid

Force is due to

1

(a)

motion

(b)

an interaction

(c)

collision

(d)

None of these

In order to reduce the loudness of a sound, we have to

1

(a)

decrease its frequency of vibration of the sound

(b)

increase its frequency of vibration of the sound

(c)

decrease its amplitude of vibration of the sound

(d)

increase its amplitude of vibration of the sound

Sparks can be seen on the electric poles, due to which wire becomes

1

(a)

loose

(b)

tight

(c)

wrinkle

(d)

None of the above

Which small objects revolve between the orbits of Mars and Jupiter?

1

(a)

Satellites

(b)

Comets

(c)

Asteroids

(d)

Meteorites

Boojho wishes to contribute in reducing air pollution. Which vehicle should he use for going to school?

1

(a)

Car

(b)

School bus

(c)

Autorickshaw

(d)

Scooter

Seed drill sows the seeds uniformly at proper______ and ______

1

(a)

distance, depth

Name two commonly known antibiotics.

1

(a)

Streptomycin, tetracycline.

Spring balance is a device used for measuring the ________ acting on the object.

1

(a)

force

Lightning conductor can __________ buildings from the effect of lightning.

1

(a)

protect

A Solar system consists of eight planets and a host of_____________ and _____________ ,

1

(a)

asteroids, comets, meteors

Most of the plastics are biodegradable

1

(a) True

(b) False

A new human individual develops from a cell called gamete.

1

(a) True

(b) False

Ball bearing is a device which converts static friction into sliding friction.

1

(a) True

(b) False

Sound waves travel faster in air than in water.

1

(a) True

(b) False

SO₂, CO and NO₂ oxides are polluting the gases.

1

(a) False

(b) True

What is the process of loosening and turning of the soil called?

1

(a)

Tilling or ploughing

How is rayon formed?

1

(a)

Rayon is obtained by chemical treatment of wood pulp.

A giant animal that is known to be existing long back in the Jurassic period became extinct. Can you name it?

1

(a)

Dinosaurs.

A single-celled animal

1

(a)

Unscramble the underlined words in the following sentences
The development of a caterpillar to an adult butterfly is termed as poommertaissh

1

(a)

metamorphosis

Can friction never be entirely eliminated?

1

(a)

Yes

Write a precaution to prevent eardrum damage.

1

(a)

Never put a sharp, pointed or hard thing into your ear.

What is lightning?

1

(a)

Lightning is an electric spark on a huge scale.

What is lateral inversion?

1

(a)

In an image formed by a mirror the left side appears on the right side and the right side appears on the left side, this is known as lateral inversion.

We were imaging a time when clean air and water may no longer be available. Why?

1

(a)

Due to environmental pollution

You must have seen the farmer plough seedlings of paddy into the field from a nursery. Give the name of this process

2

(a)

Which non-metal is used to disinfect water?

2

(a)

Like fuels, the sun also provides heat and light. What is the source of heat and light in the sun?

2

(a)

Does it mean that the net force on an object is zero if the two forces acting on it in opposite direction are equal?

2

(a)

What can we do to minimize the effect of earthquake?

2

(a)

Boojho wants to know what is pasteurization.

2

(a)

Describe how coal is formed from dead vegetation. What is this process called?

2

(a)

Define adolescence.

2

(a)

What is the cause of friction?

2

(a)

How would the disposal of garbage, etc. affect the living organisms in the river?

2

(a)

1. How can we prevent the following diseases?
   (a) Cholera (b) Typhoid (c) Hepatitis-A

   5

   (a)

2. We say fossil fuels will last only for a few hundred years. Comment.

   5

   (a)

1. Rohit while gardening observed many beautiful flowering plants. He got attracted by the brightly coloured flowers and their beautiful appearance. He was curious to know about the variation of colours in flowers and asked her biology teacher about it. Teacher told her about the plastids found in plant cells.
   (a) A particular plastid is responsible for the variation in colours of flowers. Which is it?
   (b) Name the plastids known as kitchen of the cell.
   (c) Are all plastids coloured?
   (d) Will we be able to observe plastid in an animal cell?
   (e) Identify values shown by Rohit.

   5

   (a)

2. It is much easier to burst an inflated balloon with a needle than by a finger. Explain.

   5

   (a)

1. Explain in brief about eardrum. Also explain how does it play an important role in hearing.

   5

   (a)

2. Water is one of our most precious commodities and no life can survive without it. It has been predicted that water scarcity will become the subjects of 'Wars' in the near future. Write any two ways in which water is getting polluted. Write any two measures to stop water pollution at your level.

   5

   (a)