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Subhi, a class 6 student grouped together a few changes occurring around us as:
Group 1 : Blooming of flowers, breaking of glass, vaporisation of water, sawing of wood
Group 2 : Tides in the ocean, motion of a swing, landslides, occurrence of day and night
Group 3 : Rusting, germination of seeds, burning of fire crackers, growth of a child
Group 4 : Making a paper boat, blowing air into balloon, baking a roti, heating an iron rod
Select the odd one in each group and mention the property which makes it odd.

Refer to the given Venn diagram.

Which of the following cannot be Z?

A Appearance of hair in pubic region
B Change in body shape
C Secretion of sex hormones
D None of these

Which of the following reactions cannot take place?
I. Zinc + Sulphuric acid (dilute) → Zinc sulphate + Hydrogen
II. Copper + Silver nitrate → Copper nitrate + Silver
III. Zinc + Iron sulphate → Zinc sulphate + Iron
IV. Copper + Hydrochloric acid (dilute) → Copper chloride + Hydrogen

A III and IV only
B IV only
C II only
D I and III only

The given groups categorise objects on the basis that they give light or not. Each group contains one wrong member which has been encircled. Select the group in which the wrong member is encircled INCORRECTLY.

A
B
C
D

Copper wires are used as connecting wires because

A Copper has very high melting point
B Copper wires are very thick wires
C Copper wire offers a lower resistance
D None of these

Properties of three substances X, Y and Z are given below :
X : Heavy and non-magnetic
Y : Light and non-magnetic
Z : Magnetic
If X, Y and Z are of same size and colour then, which of the following can be used to separate these particles from their mixture?

A Handpicking followed by filtration
B Winnowing followed by magnetic separation
C Magnetic separation followed by sieving
D Sublimation followed by distillation

Which two environmental changes usually cause certain animals to migrate?

A Change of season and fewer predators
B Change of season and less food
C Loss of habitat and fewer predators
D Loss of habitat and more food

Option which correctly identifies true (T) and false (F) ones.
(i) The seasonal movement of the complete population of animals from one area to another is termed migration.
(ii) Heavy and solid bones help penguins to swim through water at a speed up to 15 miles per hour.
(iii) Toucans have four clawed toes in each leg, two in front and two at the back.
(iv) Most rainforests lie between the Tropic of Cancer and the Tropic of Capricorn, that is why they are often called as tropical rainforests.

Select the incorrect match.
(i) Mohair - Angora rabbit
(ii) Merino - Vicuna
(iii) Angora wool - Angora goat
(iv) Cashmere - Kashmiri goat

A(i), (ii) and (iii) only
B(ii) only
C(ii) and (iv) only
D(i), (ii), (iii) and (iv)

Following are the different steps carried out in a waste water treatment plant. These steps are arranged in a random fashion. Select the option that arranges these steps in the correct sequence.
(i) Wastewater is passed into sedimentation tank.
(ii) Sludge is decomposed by anaerobic bacteria.
(iii) Wastewater is passed through bar screens.
(iv) Wastewater is passed to grit and sand removal tank.
(v) Solids settle at the bottom and floatable materials are removed by skimmer.
(vi) Aeration of water takes place.
(vii) Disinfection of water by adding chlorine.

A(iii) → (i) → (iv) → (v) → (ii) → (vi) → (vii)
B(iii) → (iv) → (i) → (v) → (ii) → (vi) → (vii)
C(iv) → (vi) → (v) → (iii) → (ii) → (i) → (vii)
D(iv) → (v) → (vii) → (ii) → (vi) → (i) → (iii)