The principal constituent of the atmosphere of the Earth is?
A. Oxygen
B. Carbon
C. Hydrogen
D. Nitrogen » Read More…
A. Oxygen
B. Carbon
C. Hydrogen
D. Nitrogen » Read More…
A. Convex lens
B. Concave lens
C. Curved lens
D. None of these
A. Vitamin B12
B. Vitamin A
C. Vitamin D
D. None of these
A. Thermometer
B. Oximeter
C. Spirometer
D. None of these
A. Venus
B. Mercury
C. Jupiter
D. None of these
A. Methane
B. Ammonia
C. Nitrogen
D. None of these
A. Infrared waves
B. Radio waves
C. TV waves
D. None of these