Question
State the main agents of weathering.
✓
Answer
The main agents of weathering are:
- Temperature: Temperature changes that cause the rock surface to break apart.
- Frost: Ice expands and produces pressure, causing the crevices in rock to open.
- Air: Wind blow across rock surface and carry minute particle and form layer.
- Water: Continuous movement of rain water causes braking down of rock particles into fine particles.
- Living organism: Lichen grow on the surface of rocks and produce acid which corrode the rocky surface. Weathering by living organism is called biological weathering.
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Column I
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Column II
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$(a)$
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Salivary gland
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$(i)$
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Bile juice secretion
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$(b)$
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Stomach
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$(ii)$
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$(c)$
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$(iii)$
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Saliva secretion
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$(d)$
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Rectum
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$(iv)$
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Acid release
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$(e)$
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Small intestine
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$(v)$
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Digestion is completed
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$(f)$
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Large intestine
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$(vi)$
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Absorption of water
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$(vii)$
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Release of faeces
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Figure shows four cells fixed on a board. Draw lines to indicate how you will connect their terminals with wires to make a battery of four cells.
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Column I
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Column I
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$(a)$
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Large crystals
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$(i)$
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$(b)$
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$(ii)$
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Physical change
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$(c)$
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Souring of milk
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$(iii)$
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$(d)$
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Sugar candy $(Mishri)$
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$(e)$
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$(v)$
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Chemical change
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$(f)$
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Dissolving common salt in water
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$(vi)$
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Galvanisation
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Column I
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Column II
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$a.$
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Inorganic impurities
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$i.$
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$b.$
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Organic impurities
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$ii.$
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$c.$
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$iii.$
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|
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$d.$
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Bacteria
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$iv.$
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