The most abundant element in the universe is:
A. Oxygen
B. Hydrogen
C. Carbon Dioxide
D. Silicon
The most abundant element in the Earth’s crust:
A. Oxygen
B. Hydrogen
C. Carbon Dioxide
D. Silicon
Each day human body breathe in ___ litres of air.
A. 5,000 to 10,000
B. 10,000 to 15,000
C. 15,000 to 20,000
D. 20,000 to 25,000
A device which converts chemical energy into electrical energy is called:
A. motor
B. generator
C. moving-coil meter
D. Battery
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