Previous year MCQs

General science UPPSC 2005 GS-I
Question

In cold weather, aquatic animals survive when water at the top layer of the lake freezes into ice because:

Answer & Solution

Answer: (Detailed Solution Below)

Option D: water has highest density at 4°C so underneath the top layer of ice there is layer of water

Detailed Solution:

The correct answer is “water has highest density at 4°C so underneath the top layer of ice there is layer of water”.
In cold weather, when the top layer of a lake freezes into ice, aquatic animals can survive underneath because water has its highest density at 4°C.

This means that as water cools down to 4°C, it becomes denser and sinks, while water below 4°C (up to the freezing point) becomes less dense and stays on top, eventually forming ice. This allows a layer of liquid water to remain beneath the ice, providing a habitat for aquatic life.

Similar Questions:

Statement (A): The signal of danger is made of red colour.
Reason (R): The scattering of red is least

Select the right answer with the help of code given below.
Code:
  1. A) Both A and R are true and R is the correct explanation of A
  2. B) Both A and R are true but R is not the correct explanation of A
  3. C) A is true but R is false
  4. D) A is false but R is true
The main pollutant in the smoke coming from cigarette is:
  1. A) Carbon monoxide and Dioxicine
  2. B) Carbon monoxide and Nicotine
  3. C) Carbon monoxide and Benzene
  4. D) Dioxicine and Benzene
The highest chemical pollution is caused by the industrial effluents of
  1. A) Leather industry
  2. B) Paper industry
  3. C) Rayon industry
  4. D) Textile industry
With reference to the electric potential which of the following statements is/are correct?

1. It is a scalar quantity.
2. It is a vector quantity.

Select the correct answer using the codes given below.
Codes :
  1. A) Only 1
  2. B) Only 2
  3. C) Both 1 and 2
  4. D) Neither 1 nor 2
During 1991-2001 the percentage increase in literate persons in Uttar Pradesh was:
  1. A) 18.5
  2. B) 16.7
  3. C) 13.2
  4. D) 10.5
These days yellow lamps are frequently used as street light. Which one of the following is used in these lamps?
  1. A) Sodium
  2. B) Neon
  3. C) Hydrogen
  4. D) Nitrogen
Tulsi plant has medicinal values due to the presence of the following ?
  1. A) Inorganic Acid
  2. B) Organic Acid
  3. C) Phenols and Flavonoids
  4. D) None of the above
Which of the following elements is not a Noble gas?
  1. A) Argon
  2. B) Radon
  3. C) Krypton
  4. D) Actinium
Consider the following statements:

1. Fibre optics is based on the principle of total internal reflection.
2. In optical fibre communication system power consumption is extremely low.
3. Optical fibre communications are free from radio frequency interference.
4. In India, Reliance group of Industries is engaged in the manufacture of optical fibre.

Of these statements:
  1. A) 1, 2 and 3 are correct
  2. B) 1, 2 and 4 are correct
  3. C) 1, 3 and 4 are correct
  4. D) 2, 3 and 4 are correct
Assertion (A): Some bacteria can synthesise their own food.
Reason (R): These bacteria have green matter called chloroplasts.

Codes:
  1. A) Both A and R are true and R is the correct explanation of A
  2. B) Both A and R are true but R is not the correct explanation of A
  3. C) A is true but R is false
  4. D) A is false but R is true
Today the most urbanised country of the world is
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  2. B) Japan
  3. C) Singapore
  4. D) U.S.A.
Match list-I with list-II and select the correct answer using the code given below:
List-I - List-I

A. Malaria - 1. Bone Marrow
B. Filaria - 2. Brain
C. Encephalitis - 3. Muscle
D. Leukemia - 4. Lymph node
5. Blood cells

Code:
A B C D
  1. A) 5 3 2 1
  2. B) 5 4 2 1
  3. C) 4 3 5 1
  4. D) 5 4 1 2