Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
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Force is measured in newtons.
One newton accelerates one kilogram by one metre per second squared.
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Erosion removes and transports soil or rock.
Water, wind, ice, and gravity can cause it.
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Recycling processes used materials into new products.
It can reduce waste and demand for raw resources.
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Carbon dioxide is a major greenhouse gas released by fossil-fuel use.
It traps heat in Earth's climate system.
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Wind turbines convert the kinetic energy of moving air into electricity.
It is a renewable energy source.
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Solar radiation drives weather, climate, and photosynthesis.
Other energy sources are much smaller for the surface system.
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Human cells use oxygen in cellular respiration.
The process releases energy from food molecules.
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Neutral water has equal hydrogen and hydroxide ion concentrations.
Its pH is approximately 7 at room temperature.
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Common table salt is sodium chloride.
It consists of sodium and chloride ions.
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Each water molecule has two hydrogen atoms and one oxygen atom.
Its formula is H₂O.
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Most atmospheric ozone is concentrated in the stratosphere.
It absorbs much of the Sun's harmful ultraviolet radiation.
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Nitrogen makes up about 78% of the atmosphere.
Oxygen is the second most abundant gas.
