The boiling point of water at sea level is:
a) 90°C
b) 100°C
c) 110°C
d) 120°C
Which gas do plants absorb during photosynthesis?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Hydrogen
What is the chemical formula for water?
a) CO₂
b) H₂O
c) O₂
d) NaCl
Which vitamin is produced in the human body when exposed to sunlight?
a) Vitamin A
b) Vitamin B
c) Vitamin C
d) Vitamin D
The process by which water changes from liquid to gas is called:
a) Condensation
b) Evaporation
c) Freezing
d) Melting
Which part of the human body controls balance?
a) Heart
b) Lungs
c) Inner ear
d) Stomach
Which metal is liquid at room temperature?
a) Iron
b) Mercury
c) Silver
d) Copper
The most abundant gas in Earth’s atmosphere is:
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Hydrogen
Which organ in the human body produces insulin?
a) Liver
b) Pancreas
c) Kidney
d) Heart
Sound travels fastest through:
a) Air
b) Water
c) Vacuum
d) Solid
Which gas is essential for human respiration?
a) Carbon dioxide
b) Oxygen
c) Helium
d) Nitrogen
Which planet is known as the “Red Planet”?
a) Venus
b) Mars
c) Jupiter
d) Saturn
Which of the following is NOT a renewable source of energy?
a) Solar energy
b) Wind energy
c) Coal
d) Hydropower
Which part of the human eye controls the amount of light entering?
a) Retina
b) Cornea
c) Iris
d) Lens
Which is the hardest natural substance on Earth?
a) Gold
b) Iron
c) Diamond
d) Quartz
Which force keeps planets in orbit around the Sun?
a) Magnetism
b) Gravity
c) Friction
d) Nuclear force
Which gas is used in balloons to make them float?
a) Oxygen
b) Hydrogen
c) Helium
d) Nitrogen
What is the SI unit of force?
a) Watt
b) Newton
c) Joule
d) Pascal
What is the main function of red blood cells?
a) Fight infections
b) Transport oxygen
c) Digest food
d) Produce hormones
Which planet is the largest in the Solar System?
a) Earth
b) Mars
c) Jupiter
d) Saturn
Which gas do humans exhale in large amounts?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Helium
Which simple machine is used to lift heavy objects with less effort?
a) Pulley
b) Lever
c) Screw
d) Wheel
Which disease is caused by a deficiency of Vitamin C?
a) Rickets
b) Scurvy
c) Anemia
d) Goiter
Which instrument is used to measure temperature?
a) Barometer
b) Thermometer
c) Hygrometer
d) Anemometer
Which type of energy is stored in food?
a) Kinetic energy
b) Chemical energy
c) Thermal energy
d) Nuclear energy
What is the speed of light in a vacuum?
a) 150,000 km/s
b) 200,000 km/s
c) 250,000 km/s
d) 300,000 km/s
Which of these is NOT an element?
a) Gold
b) Silver
c) Water
d) Oxygen
Which gas is known as laughing gas?
a) Nitrous oxide
b) Carbon monoxide
c) Hydrogen peroxide
d) Sulfur dioxide
Which part of the plant is responsible for photosynthesis?
a) Root
b) Leaf
c) Stem
d) Flower
Which energy source is the most environmentally friendly?
a) Coal
b) Nuclear
c) Solar
d) Oil
