1. What is the primary source of energy for the Earth?
a) Wind
b) Geothermal
c) Solar
d) Nuclear
Answer: c) Solar
2. Which of the following states of matter has a definite shape and volume?
a) Gas
b) Liquid
c) Plasma
d) Solid
Answer: d) Solid
3. What is the chemical symbol for water?
a) O2
b) H2O
c) CO2
d) H2SO4
Answer: b) H2O
4. The process by which plants make their own food is called:
a) Respiration
b) Digestion
c) Photosynthesis
d) Fermentation
Answer: c) Photosynthesis
5. What is the smallest unit of life that can function independently?
a) Tissue
b) Organ
c) Cell
d) Organism
Answer: c) Cell
6. What force pulls objects towards the center of the Earth?
a) Magnetism
b) Friction
c) Gravity
d) Electromagnetic force
Answer: c) Gravity
7. Which planet in our solar system is known for its prominent ring system?
a) Mars
b) Jupiter
c) Saturn
d) Neptune
Answer: c) Saturn
8. What is the boiling point of water at sea level in Celsius?
a) 50°C
b) 75°C
c) 100°C
d) 120°C
Answer: c) 100°C
9. In which part of the cell does cellular respiration occur?
a) Nucleus
b) Ribosome
c) Mitochondria
d) Endoplasmic reticulum
Answer: c) Mitochondria
10. What is the main gas responsible for causing climate change?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Hydrogen
Answer: c) Carbon dioxide
11. Which of the following is a renewable source of energy?
a) Coal
b) Natural gas
c) Solar energy
d) Nuclear energy
Answer: c) Solar energy
12. What is the basic unit of heredity in living organisms?
a) Gene
b) Chromosome
c) DNA
d) Protein
Answer: a) Gene
13. What type of bond holds the atoms in a water molecule together?
a) Ionic bond
b) Covalent bond
c) Hydrogen bond
d) Metallic bond
Answer: b) Covalent bond
14. Which organ in the human body is responsible for pumping blood throughout the circulatory system?
a) Lungs
b) Liver
c) Brain
d) Heart
Answer: d) Heart
15. What is the primary function of the human respiratory system?
a) Digestion
b) Circulation
c) Gas exchange
d) Waste elimination
Answer: c) Gas exchange
16. What is the most abundant gas in the Earth’s atmosphere?
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Argon
Answer: c) Nitrogen
17. Which scientific instrument is used to measure temperature?
a) Barometer
b) Thermometer
c) Hygrometer
d) Anemometer
Answer: b) Thermometer
18. What phenomenon causes the seasons to change on Earth?
a) Earth’s rotation
b) Earth’s tilt and orbit around the Sun
c) Moon’s phases
d) Solar flares
Answer: b) Earth’s tilt and orbit around the Sun
19. In what state of matter are molecules most closely packed?
a) Gas
b) Liquid
c) Solid
d) Plasma
Answer: c) Solid
20. What is the process by which a liquid turns into a gas?
a) Freezing
b) Condensation
c) Evaporation
d) Melting
Answer: c) Evaporation