Practice PPSC questions with answers and explanations.
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The nucleus contains most of the cell's genetic material.
It directs protein production and cell activities.
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Liquefied petroleum gas is mainly propane and butane.
Pressure keeps these gases liquid in cylinders.
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Coal formed from buried plant matter over geological time.
Heat and pressure changed the material into carbon-rich fuel.
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Crude petroleum contains many hydrocarbon compounds.
Refining separates it into useful fractions.
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Crude oil is heated and separated in a fractionating column.
Components condense at different heights according to boiling point.
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Petrol is a volatile petroleum fraction used in spark-ignition engines.
It contains a blend of hydrocarbons.
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Higher octane fuel resists premature ignition under compression.
This reduces knocking in suitable engines.
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Copper conducts electricity well and can be drawn into wires.
It is also relatively resistant to corrosion.
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Aluminium has a low density and good corrosion resistance.
Its alloys are widely used in aircraft.
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Mercury remains liquid at typical room temperatures.
Its toxicity has reduced its use in household instruments.
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Pencil cores are made mainly of graphite mixed with clay.
Graphite is a form of carbon.
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Calcium and magnesium ions cause hardness.
Hard water forms scale and reduces soap lather.
