OAA Science — Questions and Answers
Question 1: What is the primary source of energy for the Earth?
- The moon
- The Sun (Correct answer)
- Geothermal energy
- Wind
Correct answer: The Sun
The Sun is the ultimate source of almost all energy on Earth. Its radiant energy drives photosynthesis, powers the water cycle, and creates weather patterns, making it fundamental for sustaining life and geological processes.
Question 2: What is the process by which plants make their own food?
- Respiration
- Osmosis
- Photosynthesis (Correct answer)
- Digestion
Correct answer: Photosynthesis
Photosynthesis is the vital process by which green plants, algae, and some bacteria convert light energy into chemical energy. They use sunlight, water, and carbon dioxide to create glucose (food) and release oxygen as a byproduct.
Question 3: What is the chemical formula for water?
- CO₂
- H₂O (Correct answer)
- O₂
- H₂
Correct answer: H₂O
H₂O is the universally recognized chemical formula for water. This formula indicates that each molecule of water is composed of two hydrogen atoms bonded to one oxygen atom, a fundamental compound for all known life.
Question 4: What is the force that pulls objects toward the center of the Earth?
- Magnetism
- Friction
- Gravity (Correct answer)
- Inertia
Correct answer: Gravity
Gravity is the fundamental force of attraction that pulls objects with mass towards each other. On Earth, it is responsible for objects falling downwards and for keeping us grounded, constantly pulling everything towards the planet's center.
Question 5: What is the basic unit of life?
- Atom
- Cell (Correct answer)
- Molecule
- Organism
Correct answer: Cell
The cell is considered the basic unit of life because it is the smallest structural and functional unit of an organism that can perform all processes necessary for life. All living things, from bacteria to humans, are composed of one or more cells.
Question 6: What gas do plants take in during photosynthesis?
- Oxygen
- Carbon dioxide (Correct answer)
- Nitrogen
- Hydrogen
Correct answer: Carbon dioxide
During photosynthesis, plants absorb carbon dioxide from the atmosphere through small pores in their leaves called stomata. This carbon dioxide is then used, along with water and sunlight, to produce glucose (sugar) for energy and oxygen.
Question 7: What is the process of cell division called?
- Meiosis
- Mitosis (Correct answer)
- Fission
- Fusion
Correct answer: Mitosis
Mitosis is the process of cell division where a single parent cell divides into two identical daughter cells. This process is essential for growth, repair of damaged tissues, and asexual reproduction in many organisms, ensuring genetic continuity.
Question 8: What is the smallest planet in our solar system?
- Venus
- Earth
- Mercury (Correct answer)
- Mars
Correct answer: Mercury
Mercury is indeed the smallest planet in our solar system, as well as the closest to the Sun. Its small size and proximity to the Sun contribute to its extreme temperature variations.
Question 9: What is the main function of the heart?
- To digest food
- To circulate blood (Correct answer)
- To control body temperature
- To filter waste
Correct answer: To circulate blood
The heart's primary function is to act as a pump, circulating blood throughout the entire body. This continuous circulation delivers oxygen and nutrients to cells while removing waste products like carbon dioxide.
OAA Science
What is the primary source of energy for the Earth?