Chapter Wise Ecology & Environment MCQ’s With Explanation

Today’s Topic: Pollution and Environment Change

These are most-important and most-expected Questions for IAS Prelims General Studies paper-1 (Ecology and Environment) of UPSC Civil Service exam. Every day Himalai is coming with different subjects questions and answers with explanation analysis, these Questions will be both theoretical and fact-based. Every day preparation will make a way for success, keep up your daily IAS Exam preparation with Himalai subject wise, chapter wise and topic wise Mcq’s with answers and analysis. We are providing our daily program list so that aspirant can note it and keep a watch on Himalai Mock test blogs for updated questions and get prepared for the Exam.

 EveryDay Program List

Monday-General issues on Environmental Ecology, Bio-diversity and Climate Change

Tuesday- General Science

Wednesday- Indian Polity and Governance

Thursday- History of India and Indian National Movement

Friday- Economic and Social Development

Saturday- Indian and World Geography

Today’s Topic: Pollution and Environment Change

Q1. Consider the following statements:

  1. Organic and inorganic wastes increase the dissolved O2 (DO) content of water bodies.
  2. DO content of water is important for the survival of aquatic organisms.

Which of the statements given above is/are correct?

a) Only 1                 b) Only 2             c) Both 1 and 2                        d) Neither 1 nor 2

Ans:     B

Explanation:    Organic and inorganic wastes decrease the dissolved O2 (DO) content of water bodies. Water having DO content below 8.0 mg L-1 may be considered as contaminated. Heavily polluted waters have DO content below 4.0 mg L-1, DO content of water is important for the survival of aquatic organisms.

Q2. Which of the following factors determine the amount of dissolved O2 (DO) present in water?

1. Surface turbulence                                2. Photosynthetic activity

3. O2 Consumption by organisms            4. Decomposition of organic matter

a) Only 1 and 2                        b) Only 1, 2 and 3                    c) Only 3 and 4                        d) Only 1, 2, 3 and 4

Ans:     D

Explanation:    Organic and inorganic wastes decrease the dissolved O2 (DO) content of water bodies Water having DO content below 8.0 mg L-1 may be considered as contaminated. The surface turbulence, photosynthetic activity, O2 consumption by organisms and decomposition of organic matter are the factors which determine the amount of DO present in water.

Q3. Match the following:

List-I                                                                                                               List-II

  1. Biochemical Oxygen Demand (BOD)                                1. Measure of oxygen equivalent of the requirement for oxidation of total organic matter present in water.
  1. Chemical Oxygen Demand (COD)                                    2. The process of nutrient enrichment of water and consequent loss of species diversity.
  1. Eutrophication                                                                   3. A measure of oxygen required by aerobic decomposer for the biochemical degradation of organic materials in water.

 

Code:

A         B          C

a) 2       1          3

b) 3       2          1

c) 3       1          2

d) 1        2          3

Ans:     B

Explanation:    Biochemical Oxygen Demand (BOD) of water is a measure of oxygen required by aerobic decomposers for the biochemical degradation of organic materials in water.Chemical Oxygen Demand (COD) is the measure of oxygen equivalent of the requirement for oxidation of total organic matter present in water.Eutrophication is the process of nutrient enrichment of water, and consequent loss of species diversity.

Q4. Consider the following statements:

  1. Higher the biochemical oxygen demand (BOD) of water, higher would be the dissolved O2 (DO).
  2. Higher the temperature of water lower is the rate of dissolution of O2 in water.

Which of the statements given above is/are correct?

a) Only 1                     b) Only 2                     c) Both 1 and 2                        d) Neither 1 nor 2

Ans:     B

Explanation:    The demand for O2 is directly related to increasing input of organic wastes and is expressed as biochemical oxygen demand (BOD) of water. Higher the BOD lower would be the dissolved O2 (DO). Higher the temperature of water, lower is the rate of dissolution of O2 in water. Hence, hot wastewaters discharged from industries, when added to water bodies, also lower its DO content.

Q5. Consider the following statements:

  1. Availability of excess nutrients causes the profuse growth of algae.
  2. In bloom-infested water, body, the aquatic animals flourish.

Which of the statements given above is/are correct?

a) Only 1              b) Only 2             c) Both 1 and 2                        d) Neither 1 nor 2

Ans:     A

Explanation:    Availability of excess nutrients cause a profuse growth of algae (algal bloom), especially the blue-green algae. Such algal blooms may totally cover the water surface, and cause a release of toxins in water, and sometimes cause a deficiency of oxygen in the water. Thus in bloom-infested water body the growth of other algae may be inhibited due to toxins, and aquatic animals may die due to toxicity or lack of oxygen.

Q6. Which of the following are waterborne diseases?

  1. Jaundice                     2. Cholera                     3. Typhoid                     4. Amoebiasis

a) Only 1, 2 and 3                b) Only 1, 2 and 4              c) Only 3 and 4                        d) Only 1, 2, 3 and 4

Ans:     D

Explanation:    Domestic sewage contains pathogens like virus, bacteria, parasitic protozoa and worms. Contaminated water, therefore, can carry the germs of water-borne diseases like jaundice, cholera, typhoid, amoebiasis, etc. Such contamination may make the water unfit for drinking bathing and swimming.

Q7. Which of the following are found in Domestic sewage?

  1. Virus                     2. Bacteria                     3. Parasitic protozoa                    4. Worms

a) Only 1 and 2                        b) Only 1 and 3                       c) Only 2, 3 and 4                    d) Only 1, 2, 3 and 4

Ans:     D

Explanation:    Domestic sewage contains pathogens like virus, bacteria, parasitic protozoa and worms. Contaminated water, therefore, can carry the germs of water-borne diseases like jaundice, cholera, typhoid, amoebiasis, etc.

Q8. Match the following:

List-I                                        List-II

  1. Minamata disease                      1. Mercury
  2. Itai-itai disease                           2. Arsenic
  3. Black-foot disease                     3. Cadmium

Code:

A         B          C

a) 3        2          1

b) 2       1          3

c) 1       2          3

d) 1       3          2

Ans.     D

Explanation:    Heavy metal contamination of water can cause serious health problems. Mercury poisoning may cause Minamata disease. Cadmium pollution can cause Itai-Itai disease. Chronic exposure to arsenic causes black-foot disease.

Q9. Consider the following statements:

  1. Excess fluoride in drinking water causes teeth deformity, hardened bones, and stiff and painful joints.
  2. Overexploitation of groundwater may contaminate groundwater.

Which of the statements given above is /are correct?

a) Only 1                     b) Only 2         c) Both 1 and 2                        d) Neither 1 nor 2

Ans:     C

Explanation:    Teeth deformity, hardened bones and stiff and painful joints (skeletal fluorosis) can be caused due to excess of fluoride in drinking water. Overexploitation of groundwater may possibly initiate leaching of arsenic from soil and rock sources and contaminate groundwater.

Q10. Which of the following diseases are caused due to Arsenic?

  1. Diarrhea                     2. Peripheral neuritis                     3. Hyperkeratosis

a) Only 1 and 2                        b) Only 1 and 3                       c) Only 2 and 3                        d) 1, 2 and 3

Ans.     D

Explanation:    Chronic exposure to arsenic causes black-foot disease. Arsenic causes diarrhea, peripheral neuritis, and hyperkeratosis, and also lung and skin cancers.

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