Our Home: Earth, a Unique Life Sustaining Planet — Quiz

Q1. Out of the eight planets in our solar system, the relatively small and rocky planets are

• A. Jupiter, Saturn, Uranus and Neptune
• B. Mars, Jupiter, Saturn and Uranus
• C. Mercury, Mars, Jupiter and Saturn
• D. Mercury, Venus, Earth and Mars

Q2. If the Earth were closer to the Sun than its present distance, the most likely outcome would be that

• A. The temperature would be too high and all the water would evaporate
• B. The temperature would drop and water would freeze
• C. The atmosphere would become thicker and trap heat
• D. Earth's gravity would become weaker

Q3. Scientists continue to study Mars closely because

• A. Mars is the largest planet of our solar system
• B. Mars lies at the edge of the Sun's habitable zone and may have had liquid water and conditions for simple life in the past
• C. Mars is closer to the Sun than Earth and is the hottest planet
• D. Mars has rings just like Saturn

Q4. The orbits of most planets, including Earth, are almost circular. This near-circular orbit of Earth helps because it

• A. Makes Earth move faster than other planets
• B. Increases the amount of food crops grown
• C. Keeps the amount of sunlight and heat nearly steady throughout the year, preventing extreme summers and winters
• D. Increases Earth's gravity

Q5. Compared to Earth, the atmosphere on Mars is about 100 times thinner, and Mercury has no atmosphere at all. This is mainly because

• A. Mars and Mercury have weaker gravity, so much of their atmospheric gases escaped into space
• B. Mars and Mercury are made of gases
• C. Mars and Mercury are at a colder distance from the Sun
• D. Mars and Mercury have very thick ozone layers

Q6. Earth's magnetic field acts like a protective shield against tiny high-energy particles. The particles that come from the Sun are called

• A. Cosmic rays
• B. Solar wind
• C. UV rays
• D. Radio waves

Q7. The variety of landforms, rocks, soils etc. on Earth, along with the processes that shape and alter them, is called

• A. Biodiversity
• B. Hydrosphere
• C. Geodiversity
• D. Atmosphere

Q8. In the presence of sunlight, plants take carbon dioxide from the air and water from the soil to

• A. Form ozone in the atmosphere
• B. Cause earthquakes in the crust
• C. Prepare food by photosynthesis, releasing oxygen
• D. Increase the gravity of Earth

Q9. Water is essential for animals because, among other things, it

• A. Acts as a fuel to burn in the body
• B. Replaces the role of sunlight in plants
• C. Forms the ozone layer in their cells
• D. Regulates body temperature, aids digestion and ensures hydration

Q10. In asexual reproduction

• A. Two parents are involved and offspring show variation
• B. Half of the genetic material comes from each parent
• C. Pollination must always take place
• D. A single parent produces new individuals that are exact copies of itself

Q11. Hydra, a simple animal, reproduces asexually by

• A. Growing tiny buds on its body that break off and grow into new individuals
• B. Laying many eggs in water like frogs
• C. Releasing pollen into the air
• D. Joining sperm and egg cells inside its body

Q12. In a flowering plant, pollen grains found inside the anther of a flower are

• A. Decomposers that break down dead matter
• B. The male gametes
• C. The female gametes that develop into seeds
• D. The water-storing cells of the plant

Q13. In animals like fish and frogs, fertilisation usually takes place

• A. Inside the body of the female only
• B. In the soil where eggs are laid
• C. In the water, where male and female release sperm and eggs that combine to form the zygote
• D. On dry leaves after the eggs are hatched

Q14. The biggest environmental challenges we face today, together known as the 'triple planetary crisis', are

• A. Earthquakes, volcanoes and tsunamis
• B. Population growth, traffic and noise
• C. Soil erosion, deforestation and mining
• D. Climate change, biodiversity loss and pollution

Q15. The Montreal Protocol (1987) helped allow the ozone layer to slowly recover by reducing harmful chemicals called

• A. Chlorofluorocarbons (CFCs)
• B. Carbon dioxide and methane
• C. Sulphur dioxide and nitric acid
• D. Sodium and potassium salts