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

Legumes, such as beans, peas, and lentils, help increase soil fertility by fixing atmospheric nitrogen. They have symbiotic bacteria (Rhizobium) in their root nodules that convert nitrogen from the air into a form that plants can use, enriching the soil with essential nutrients.

• Option A: Cereals
  Incorrect. Cereals consume nutrients from the soil and generally do not replenish them.

• Option B: Fibre Crops
  Incorrect. Fibre crops like cotton are nutrient-demanding and do not aid in nitrogen fixation.

• Option C: Legumes
  Correct. Legumes improve soil fertility through nitrogen fixation.

• Option D: Root Crops
  Incorrect. Root crops like potatoes may deplete certain nutrients and do not contribute significantly to

The correct answer to the multiple-choice question is:

D. Verkhoyansk (Russia)

Explanation:

The coldest place on Earth (based on recorded temperatures) is in Siberia, Russia — specifically:

• Verkhoyansk and Oymyakon are both extremely cold towns located in the Sakha Republic of eastern Russia.

• Verkhoyansk has recorded temperatures as low as -67.8°C (-90°F), making it one of the coldest inhabited places on Earth.

 Why the other options are wrong:

• A. Halifax (Canada):
  Cold in winter, but nowhere near the coldest. Temperatures can go below freezing, but typically around -10°C to -20°C.

• B. Chicago (USA):
  Has cold winters, especially with wind chill, but again not even close to being the coldest. Typical winter lows are around -10°C to -25°C during cold snaps.

• C. Siachen (India-Pakistan border):
  Very cold and located at high altitude, often dipping below -50°C, especially in winter.
  It is one of the coldest military conflict zones, but not the coldest place on Earth.

Summary:

• Verkhoyansk (Russia) – One of the coldest inhabited places on Earth.

•  Others are cold, but not extreme enough to be the coldest overall.

A solar eclipse occurs when the moon comes directly between the sun and the earth. This alignment blocks the sunlight from reaching certain areas on Earth, either partially or totally, depending on the observer's location.

• Option A: Lunar eclipse
  Incorrect. A lunar eclipse occurs when the earth comes between the sun and the moon.

• Option B: Solar eclipse
  Correct. This happens when the moon is positioned between the sun and the earth.

• Option C: Side real day
  Incorrect. A sidereal day refers to the time taken by Earth to complete one rotation relative to distant stars, not related to the eclipse.

• Option D: Full moon day
  Incorrect. A full moon occurs when the earth is between the sun and the moon, which is the opposite of a solar eclipse.

• Option A: Acacia – Incorrect. Acacia trees are primarily known for gum (e.g., gum arabic), not turpentine oil.

• Option B: Chir pine – Correct. Chir pine produces resin from which turpentine oil is extracted through steam distillation.

• Option C: Myrobalans – Incorrect. Myrobalans are used in traditional medicine and tanning but are not a source of turpentine.

• Option D: Kusum – Incorrect. Kusum is used for its oil in hair care and soap but not for turpentine oil.