Given below are statements about the harmful effects of weeds on crop plants.
(i) They interfere in harvesting.
(ii) They help crop plants to grow healthily.
(iii) They compete with crop plants for water, nutrients, space and light.
(iv) They affect the plant growth.
Choose the correct combination of statements.

1

(a)

(i), (iii) and (iv)

(b)

Only (iii)

(c)

(iii) and (iv)

(d)

(i), (ii), (iii) and (iv)

Which is not a property of non-metal?

1

(a)

Ductility

(b)

Solid state

(c)

Can be conductors

(d)

All.

Which of the following is not a constituent of petroleum?

1

(a)

Paraffin wax

(b)

Lubricating oil

(c)

Petrol

(d)

Coke

The structural and functional unit of life called cell was discovered by

1

(a)

Robert Boyle

(b)

Charles Darwin

(c)

Robert Koch

(d)

Robert Hooke

Sex chromosomes in a female body are

1

(a)

X

(b)

Y

(c)

XX

(d)

XY

During dry weather while combing hair, sometimes we experience hair flying apart. The force responsible for this is

1

(a)

force of gravity

(b)

electrostatic force

(c)

force of friction

(d)

magnetic force

The maximum displacement of a vibrating body from its mean position is called

1

(a)

frequency

(b)

time period

(c)

amplitude

(d)

None of the above

Consider the list of terms given below:
(i) Tsunami
(ii) Landslide
(iii) Floods
(iv) Lightning
Earthquakes can cause

1

(a)

(i), (ii) and (iii)

(b)

(ii) and (iv)

(c)

(ii), (iii) and (iv)

(d)

(iii) and (iv)

The change in seasons on the earth occurs because

1

(a)

the distance between the earth and the sun is not constant

(b)

the axis of rotation of the earth is parellel to the plane of its orbit

(c)

the axis of rotation of the Earth is perpendicular to the plane of its orbit

(d)

the axis of rotation of the Earth is tilted with respect to the plane of its orbit

A pond contains clean water. Which of the following activities will produce least pollution of water?

1

(a)

Washing clothes in the pond

(b)

Bathing animals in the pond

(c)

Washing motor vehicles in the pond

(d)

Swimming in the pond

Damaged seeds would .............. on top of water.

1

(a)

float

A worldwide campaign against _________ has finally led to its eradication from most parts of the world.

1

(a)

small pox.

Friction depends on the _________ of surfaces.

1

(a)

nature

Some objects can be charged by ________ with other objects.

1

(a)

rubbing

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

1

(a)

asteroids, comets, meteors

Melamine is a thermoplastic.

1

(a) True

(b) False

Each sperm is a single cell.

1

(a) True

(b) False

Use of lubricants increases the friction.

1

(a) True

(b) False

Only to and fro motion of an object is called vibration

1

(a) True

(b) False

Water which is suitable for drinking is called soft water.

1

(a) True

(b) False

Where is the sprinkler water system useful?

1

(a)

Sprinkle water system is useful on the uneven land and at the land where water is not available. It is good for sandy soil.

Name the material that is used to make ropes for rock climbing.

1

(a)

Nylon.

Name the biosphere reserve where the plants and animals are found similar to the upper Himalayan peaks.

1

(a)

Pachmarhi Biosphere Reserve.

A group of similar cells performing a specific function

1

(a)

Tissue

When does puberty end?

1

(a)

Puberty ends when an adolescent reaches reproductive maturity

How can fluid friction be minimized?

1

(a)

Changing the shape of machine

Does sound travel through all mediums?

1

(a)

Yes, it travels through all mediums such as solid, liquid and gases

The process of transferring of charge from a charged object to the Earth.

1

(a)

Earthing

How many kinds of nerve cells are there in retina?

1

(a)

There are two kinds of cells :
(i) Cones: Sensitive to bright light.
(ii) Rods: Sensitive to dim light.

Define potable water

1

(a)

Water that is suitable for drinking

Terms related to agricultural practices are given below. Rearrange them in the correct sequence.harvesting, sowing, manuring, tilling and ploughing, irrigation, weeding

2

(a)

A given non-metal forms sulphuric acid on reacting with nitric acid. Identify the non-metal.

2

(a)

If you burn a candle and coal, what is the difference in their burning?

2

(a)

Boojho wants to know how we take advantage of the knowledge that pressure can be increased or decreased by changing the area on which a force acts.

2

(a)

What is an earthquake? What is its cause?

2

(a)

Shikha while teaching her sister about microbes explained that microbes are useful to humans. Hearing this, her sister Sneha got confused as she knew that her Uncle was suffering from TB caused by microbes. She asked this to Shikha. Shikha appreciated Sneha was asking this question and explained her.
(i) What are microbes?
(ii) How are microbes helpful to humans?
(iii) Mention two diseases other than TB caused by microbes.
(iv) Identify the values shown by Sneha.

2

(a)

Write the difference between coke and coal

2

(a)

What are sex hormones? Why are they named so? State their functions.

2

(a)

Imagine that an object is falling through a long straight glass tube held vertical, air has been removed completely from the tube. The object does not touch the walls of the tube. Will the object experience any force of friction?

2

(a)

Why does the increased level of nutrients in the water affect the survival of aquatic organisms?

2

(a)

1. Write a short note on. Useful micro-organisms.

   5

   (a)

2. The substance A is a fossil fuel. It occurs deep below the earth's crust in certain areas. Another fossil fuel B is found above the substance A. When A is subjected to a process C, a number of different products (fractions) are collected at different temperature ranges which have different uses. A special grade of product D obtained in this process is used as aviation fuel in jet aeroplanes. The product D is also used in stoves, lamps, etc
   Now give the answer of the following questions.
   (a) What are the substances, A and B?
   (b) Write the physical states of substances A and B.
   (c) What is the process C called?
   (d) Name the product D.

   5

   (a)

1. (a) A jelly-like substance is present in a cell. What is it called as? Also give its function.
   (b) Give the meaning of protoplasm. Name the four elements which make up major part of protoplasm.

   5

   (a)

2. It is difficult to cut cloth using a pair of scissors with blunt blades. Explain.

   5

   (a)

1. An alarm bell is kept inside a vessel as shown in figure. A person standing close to it can distinctly hear the sound of alarm. Now, if the air inside the vessel is removed completely, how will the loudness of alarm get affected for the same person?
   

   5

   (a)

2. Complete the crossword puzzle with the help of clues given below
   
   Across:
   (i) Pollutant which is used in refrigerators and air conditioners. (18)
   (iii) Produced on incomplete combustion of fuels. (14) 6. This chemical protects our crops and is washed into water bodies from the field. (9) Down:
   (ii) This layer protects us from harmful ultraviolet rays. (5)
   (iv) It is essential for combustion. (6)
   (v) Disease which is caused by drinking contaminated water. (7)
   (iv) River which is famous in India and sustains most of the northern, central and eastern Indian population. (5)

   5

   (a)