Free Environment and Atmosphere MCQs with Answers

141. Which of the following ocean is the most polluted ocean of the world?

• A. Indian Ocean
• B. North Pacific Ocean
• C. Arctic Ocean
• D. None of the above

Explanation: The North Pacific is often identified in general-knowledge questions as the most polluted ocean region, partly because it contains the Great Pacific Garbage Patch and receives heavy shipping and coastal inputs. The exact ranking depends on the type of pollution measured.

142. Smallest animal is _________?

• A. Skunk
• B. Gorilla
• C. Tiger
• D. Cat

Explanation: Among the animals listed, the skunk is generally the smallest in body size; gorillas and tigers are much larger, and ordinary cats are usually heavier. The question is asking for the smallest listed animal, not the smallest animal species overall.

143. Which of the following ocean is the warmest ocean of the world?

• A. Indian Ocean
• B. Arctic Ocean
• C. North Pacific Ocean
• D. None of the above

Explanation: The Indian Ocean is generally the warmest ocean because much of it lies in the tropics and it has limited exchange with cold polar waters. The Arctic Ocean is the coldest, while the Pacific has a wider temperature range.

144. Which is the most abundant element in the atmosphere?

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

Explanation: Nitrogen makes up about 78% of Earth's atmosphere by volume, far more than oxygen at about 21%. Hydrogen and nickel occur only in trace amounts in air.

145. Instrument of rain gauge is _________?

• A. Drosometer
• B. Ombrometer
• C. Micrometer
• D. Pyrometer

Explanation: An ombrometer, also called a rain gauge or pluviometer, measures the amount of rainfall received at a location. A pyrometer measures high temperature, while a micrometer measures very small lengths.

146. The difference in the duration of day and night increases as one moves from:_________?

• A. West to East
• B. East and west of the prime meridian
• C. Equator to poles
• D. None of these

Explanation: Day-night inequality increases from the equator toward the poles because Earth's axial tilt produces greater seasonal variation at higher latitudes. At the equator, day and night remain nearly equal throughout the year.

147. Underground water and the water on the earth's surface is called ?

• A. Mezosphere
• B. Ionosphere
• C. Hydrosphere
• D. None of these

Explanation: The hydrosphere includes all of Earth’s water, including oceans, rivers, glaciers, groundwater and water vapour. Mesosphere and ionosphere are layers or regions of the atmosphere, not water reservoirs.

148. Scientific study of the Algae is known as ___________?

• A. Phycology
• B. Pomology
• C. Oneriology
• D. Trichology

Explanation: Phycology, also called algology, is the branch of biology concerned with algae. Pomology studies fruits, while trichology concerns hair.

149. The Scientific Study of Caves are know as _________ ?

• A. Haematology
• B. Speleology
• C. Oology
• D. Oneriology

Explanation: Speleology is the scientific study and exploration of caves, including their geology, biology and formation. Haematology deals with blood, whereas oology concerns eggs.

150. The scientific study of spiders is called __________ ?

• A. Arachnology
• B. Osteology
• C. Pomology
• D. None of these

Explanation: Arachnology studies spiders and other arachnids such as scorpions and ticks. Osteology is the study of bones, so it is unrelated despite the similar scientific suffix.