Free Environment and Atmosphere MCQs with Answers

81. Volcanoes are usually located on ________?

• A. Divergent plate boundaries
• B. Convergent plate boundaries
• C. Hotspots
• D. All of these

Explanation: Volcanoes occur at divergent boundaries, convergent boundaries, and mantle hotspots. Therefore, all the listed locations can commonly host volcanoes.

82. Which ocean does not commonly experience tropical cyclones ?

• A. Western Pacific
• B. North Atlantic
• C. South Atlantic
• D. Indian Ocean

Explanation: The South Atlantic rarely experiences tropical cyclones because sea-surface temperatures are generally too cool and strong vertical wind shear disrupts their formation. The other listed oceans commonly produce such storms.

83. Study of fruit is called ___________?

• A. Pomology
• B. Plriculture
• C. Sericulture
• D. Apiculture

Explanation: Pomology is the branch of horticulture concerned with fruit and fruit cultivation. Sericulture concerns silkworms, while apiculture concerns honeybees.

84. The Aurora Borealis, also known as ________?

• A. Western lights
• B. Southern lights
• C. Eastern lights
• D. Northern lights Science

Explanation: Aurora Borealis is the northern lights, caused when charged particles from the Sun interact with gases in Earth’s upper atmosphere near the magnetic poles. The corresponding southern display is Aurora Australis.

85. Main constituent in air is ___________?

• A. Oxygen
• B. Nitrogen
• C. Hydrogen
• D. Helium

Explanation: Nitrogen makes up about 78% of dry air, making it the main constituent. Oxygen is second at about 21%, while hydrogen and helium occur only in trace amounts.

86. What is the percentage of salt water on earth surface?

• A. 93%
• B. 95%
• C. 97%
• D. 76%

Explanation: About 97% of Earth’s water is salt water, found mainly in the oceans and seas. Only roughly 3% is fresh water.

87. The maximum risk to air travel is from?

• A. Clouds
• B. Rainfall
• C. Fogs
• D. Strong Winds

Explanation: Fog is especially hazardous to air travel because it sharply reduces visibility during take-off, landing, and ground movement. Strong winds can also be dangerous, but fog is the standard answer for visibility-related aviation risk.

88. Mercury is the closest planet to the Sun, but Venus is hotter than Mercury because of its_________?

• A. Pressure
• B. axis
• C. atmosphere
• D. surface

Explanation: Venus has a very dense carbon-dioxide atmosphere that produces an intense greenhouse effect and traps heat. Mercury has almost no atmosphere, so it cannot retain heat as effectively.

89. Which part of the atmosphere are you breathing right now?

• A. Bathysphere
• B. Stratosphere
• C. Troposphere
• D. Lonosphere

Explanation: Humans live and breathe in the troposphere, the lowest atmospheric layer where most air, water vapour, clouds, and weather occur. The stratosphere lies above it.

90. Our atmosphere consists of__________ CO2?

• A. 0.03 to 0.04% CO2
• B. 0.3 to 0.4% CO2
• C. 3 to 4% CO2
• D. None of these

Explanation: Carbon dioxide forms roughly 0.04% of the atmosphere today, commonly stated in older texts as 0.03 to 0.04%. The other ranges are far too high for atmospheric CO₂.