People, Development and Environment MCQ - People, Development and Environment Section 1

A. About 97.5 per cent of the total volume of water available on the earth is salty
 True — Around 97.5% of Earth’s water is in oceans and seas and is saline, leaving very little as freshwater.

B. 80 per cent of the water available to us for use comes in bursts as monsoons
True — A large proportion of usable freshwater in India (and many tropical areas) arrives seasonally during monsoons.

C. About 2.5 per cent of the total water available on the earth is polluted water and cannot be used for human activities
Not true — About 2.5% of total water is freshwater, not polluted water. Though freshwater resources can be polluted, the 2.5% refers to freshwater available in glaciers, groundwater, etc.

D. Possibility is that some big glaciers will melt in the coming ten-fifteen years and sea level will rise by 3-4 meters all over the earth
Broadly true in terms of glacier melting, but exaggerated on sea level rise; scientists project sea level to rise by a few centimeters to around a meter by the end of the century, not 3–4 meters in just 10–15 years.

Answer: C is not true.

• Option A: Sun is moving around the earth
   Incorrect. This is a geocentric view, which has been scientifically disproven. The Earth orbits the Sun, not the other way around.
• Option B: Revolution of the earth around the Sun on its orbit
   Partially true, but not complete. Revolution alone doesn’t cause seasons unless the tilt of the axis is also considered. Without tilt, every place would receive the same type of light year-round.
• Option C: Rotation of the earth around its axis
   Incorrect. Earth's rotation causes day and night, not seasons.
• Option D: Because Earth is tilted when it revolves around the Sun
  Correct answer. The tilt + revolution together cause changing angles of sunlight, which leads to seasonal changes.

• Option A: Tall grass 
  Correct. Tall grasses dominate the savanna biome, often growing up to 2–3 meters during the wet season. This is the most accurate description of savanna vegetation.

• Option B: Scrub jungle 
  This refers more to arid or semi-arid regions (like thorn forests), not typical of savannas.

• Option C: Short grass 
   Found in temperate grasslands (like prairies or steppes), not in tropical savannas.

• Option D: Trees 
   Trees are sparse in savannas due to the seasonal droughts and fires. While present, they’re not the dominant vegetation.

• Option A: Madhya Pradesh 
   Home to dams like Bargi and Indira Sagar, but not Tehri.

• Option B: Rajasthan 
   Has water projects like Bisalpur Dam, but Tehri is not here.

• Option C: Haryana 
   No major hill rivers to support a project like Tehri Dam.

• Option D: Uttaranchal (now Uttarakhand) 
   Correct Answer. Tehri Dam is located here, in the Himalayan region of India.