Free Environment and Atmosphere MCQs with Answers

31. In night, when photosynthesis is stopped, plants__________?

• A. take in Carbon Dioxide
• B. give off Oxygen
• C. give off Carbon Dioxide
• D. None of these

Explanation: Photosynthesis stops or greatly decreases in darkness, but respiration continues in plant cells. Respiration uses oxygen and releases carbon dioxide, so plants give off carbon dioxide at night.

32. About 50% of the Earth's crust, including the waters on the Earth and atmosphere, is?

• A. Oxygen
• B. Cabon Dioxide
• C. Silicon
• D. Clay

Explanation: Oxygen forms about 46% of the Earth's crust by mass, making it the most abundant crustal element. The figure is often rounded to about 50%, while carbon dioxide and clay are not elemental components in this sense.

33. Acid rain is mainly caused by emissions of __________ in the atmosphere?

• A. Sulfur Dioxide and Potassium Nitrate
• B. Sulfur and Charcoal
• C. Nitrogen Oxide and Potassium Nitrate
• D. Sulfur Dioxide and Nitrogen Oxide

Explanation: Sulfur dioxide and nitrogen oxides react with atmospheric moisture to form sulfuric and nitric acids, which fall as acid rain. Potassium nitrate is not a principal atmospheric emission responsible for this process.

34. In general, wind speed of 10 -13 kph caused_______?

• A. minor or no damage
• B. considerable damage
• C. severe damage
• D. extreme damage

Explanation: A wind speed of 10 to 13 kph is only a gentle breeze on the Beaufort scale, so it generally causes minor or no damage. Considerable or severe damage requires much stronger winds.

35. Water covers __________ of the Earth's surface?

• A. 61%
• B. 67%
• C. 71%
• D. 76%Biological Sciences

Explanation: Water covers about 71% of Earth's surface, while land covers roughly 29%. Most of this water is in the oceans.

36. Who is considered the founder of meteorology?

• A. Aristotle
• B. Plato
• C. Einstein
• D. Newton

Explanation: Aristotle is commonly called the founder of meteorology because his work Meteorologica systematically discussed weather, winds, clouds and related atmospheric phenomena. Einstein and Newton were chiefly associated with physics, not the founding of meteorology.

37. The source of oxygen in photosynthesis is

• A. water
• B. salts
• C. minerals
• D. glucose

Explanation: The oxygen released during photosynthesis comes from the splitting of water molecules in the light-dependent reactions. Carbon dioxide supplies the carbon used to make glucose, not the released oxygen.

38. The instrument used to measure wind speed is?

• A. Anemometer
• B. Barometer
• C. Hydrometer
• D. Hygrometer

Explanation: An anemometer measures wind speed, often with rotating cups or blades. A barometer measures air pressure, while a hygrometer measures humidity.

39. The Carbon Dioxide in the atmosphere, by volume, is_______?

• A. 0.039%
• B. 3.9%
• C. 13%
• D. 30%Chemistry

Explanation: Carbon dioxide makes up about 0.04% of the atmosphere by volume, historically often quoted as 0.039%. The larger percentages listed would be far above its actual atmospheric concentration.

40. Meteorology is the study of?

• A. Seasons
• B. Atmosphere
• C. Air and sounds
• D. Winds and clouds

Explanation: Meteorology is the scientific study of the atmosphere and its short-term phenomena, including weather, winds, clouds and precipitation. Seasons are related to astronomy and climate but do not define the whole field.