The main function of the human kidneys is:
A. Pump blood
B. Filter blood and remove waste
C. Produce hormones
D. Digest food
Which gas do humans exhale during breathing?
A. Oxygen
B. Hydrogen
C. Carbon dioxide
D. Nitrogen
The type of energy stored in a stretched rubber band is:
A. Chemical energy
B. Kinetic energy
C. Thermal energy
D. Potential energy
Which planet is known for its rings?
A. Mercury
B. Earth
C. Saturn
D. Venus
The SI unit of force is:
A. Joule
B. Watt
C. Volt
D. Newton
The process of changing a liquid into solid is called:
A. Melting
B. Evaporation
C. Condensation
D. Freezing
Which part of the human eye helps focus light on the retina?
A. Iris
B. Cornea
C. Lens
D. Pupil
The chemical symbol for sodium is:
A. S
B. Na
C. So
D. Sm
The main source of energy for the Earth is:
A. Wind
B. Fossil fuels
C. Sun
D. Water
Which type of blood cells help in clotting?
A. Red blood cells
B. White blood cells
C. Platelets
D. Plasma