The main component of the Earth’s atmosphere is:
A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Hydrogen
Which planet is known as the Morning Star or Evening Star?
A. Mars
B. Venus
C. Mercury
D. Jupiter
Which organ is responsible for producing bile in humans?
A. Stomach
B. Liver
C. Pancreas
D. Kidney
Which gas do plants absorb from the atmosphere for photosynthesis?
A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Hydrogen
The speed of light in vacuum is approximately:
A. 300,000 km/s
B. 30,000 km/s
C. 3 × 10^8 m/s
D. 3,000 km/s
Which simple machine is a seesaw?
A. Pulley
B. Lever
C. Inclined plane
D. Wheel and axle
Which organ controls balance in humans?
A. Cerebrum
B. Cerebellum
C. Medulla oblongata
D. Hippocampus
Which blood component helps in clotting?
A. Red blood cells
B. White blood cells
C. Platelets
D. Plasma
Which force opposes motion between two surfaces in contact?
A. Gravity
B. Magnetism
C. Friction
D. Buoyancy
The center of an atom is called:
A. Electron cloud
B. Nucleus
C. Proton
D. Neutron