Consider the following statements : Activated sludge process can be said to comprise : 1. Conversion of dissolved organic matter into biological flocs 2. Removal of dissolved BOD of the waste water 3. Digestion of the sludge Which of these statements are correct ? (a) 1, 2 and 3 (b) 1 and 2 only (c) 2 and 3 only (d) 1 and 3 only

Consider the following statements :
 Activated sludge process can be said to comprise :
 1. Conversion of dissolved organic matter into biological flocs
 2. Removal of dissolved BOD of the waste water
 3. Digestion of the sludge
 Which of these statements are correct ?
 (a) 1, 2 and 3 (b) 1 and 2 only (c) 2 and 3 only (d) 1 and 3 only
by

1 Answer

Answer :

(b) 1 and 2 only
by

Related questions

Use of chlorine in the treatment of sewage (A) Helps in grease separation (B) Increases the biological oxygen demand (BOD) (C) Causes bulking of activated sludge (D) Aids in flocculation

Description : Use of chlorine in the treatment of sewage (A) Helps in grease separation (B) Increases the biological oxygen demand (BOD) (C) Causes bulking of activated sludge (D) Aids in flocculation

Last Answer : (A) Helps in grease separation

Consider the following statements. The following factors relate to the process of coagulation : 1. Percentage removal is higher when turbidity is more 2. Additional of activated silica aids in the process of coagulation 3. pH of water is an important consideration for selecting a coagulant Which of the following statements are correct ? a) 1, 2 and 3 b) 1 and 2 only c) 2 and 3 only d) 1 and 3 only

Description : Consider the following statements. The following factors relate to the process of coagulation : 1. Percentage removal is higher when turbidity is more 2. Additional of activated silica aids in the process of coagulation 3. pH of water ... 1, 2 and 3 b) 1 and 2 only c) 2 and 3 only d) 1 and 3 only

Last Answer : a) 1, 2 and 3

Pick up the incorrect statement from the following: A. The process of decomposing the organic matter under controlled anaerobic conditions, is called sludge digestion B. Sludge digestion is carried out in sludge tank C. The gases produced in sludge digestion process, contain 75% carbon dioxide D. The gases produced in sludge digestion process, contain 75% methane

Description : Pick up the incorrect statement from the following: A. The process of decomposing the organic matter under controlled anaerobic conditions, is called sludge digestion B. Sludge digestion is carried ... contain 75% carbon dioxide D. The gases produced in sludge digestion process, contain 75% methane

Last Answer : ANS: C

Pick out the correct statement. (A) Chemical oxygen demand (COD) is a measure of chemically oxidisable organic matter present in water (B) COD is determined by oxidising the organic matter present in water with potassium dichromate in cone, sulphuric acid solution at boiling temperature for specified time (C) COD is related to BOD of a given waste in water but the relationship varies for different wastes. Typically COD of potable water may be 1-2 mg/litre (D) All (A), (B) and (C)

Description : Pick out the correct statement. (A) Chemical oxygen demand (COD) is a measure of chemically oxidisable organic matter present in water (B) COD is determined by oxidising the organic matter present in water with potassium dichromate ... of potable water may be 1-2 mg/litre (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre)? (A) Lagooning (B) Activated carbon adsorption (C) Biological oxidation pond (D) Chemical coagulation

Description : Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre)? (A) Lagooning (B) Activated carbon adsorption (C) Biological oxidation pond (D) Chemical coagulation

Last Answer : (B) Activated carbon adsorption

Select the correct statement from the following. (a) Biogas is produced by the activity of aerobic bacteria on animal waste. (b) Methanobacterium is an aerobic bacterium found in rumen of cattle. (c) Biogas, commonly called gobar gas, is pure methane. (d) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.

Description : Select the correct statement from the following. (a) Biogas is produced by the activity of aerobic bacteria on animal waste. (b) Methanobacterium is an aerobic bacterium found in rumen of ... sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.

Last Answer : (d) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.

Pick out the wrong statement.(A) Biological oxygen demand (BOD) is a characteristic and not a constituent of water (B) BOD is a measure of the amount of oxygen which will be demanded & used in 5 days by the biological decomposition of the organic matter present in water stream present as food for the living organism (C) BOD is expressed in mg/litre (typically, BOD=2.5 mg/litre for potable water) (D) None of these

Description : Pick out the wrong statement. (A) Biological oxygen demand (BOD) is a characteristic and not a constituent of water (B) BOD is a measure of the amount of oxygen which will be demanded & used in 5 days ... BOD is expressed in mg/litre (typically, BOD=2.5 mg/litre for potable water) (D) None of these

Last Answer : (D) None of these

During sewage treatment, effluent from which one of the following treatment units has minimum wt/vol amount of suspended solids? (a) Detritus channel (b) Primary sedimentation tank (c) Secondary sedimentation tank (d) Activated sludge process aeration tank

Description : During sewage treatment, effluent from which one of the following treatment units has minimum wt/vol amount of suspended solids? (a) Detritus channel (b) Primary sedimentation tank (c) Secondary sedimentation tank (d) Activated sludge process aeration tank

Last Answer : (d) Activated sludge process aeration tank

Consider the following statements: The time of BOD assimilation in a stream can be affected by 1. Ratio of stream depth to flow width. 2. Stream BOD value 3. BOD rate constant. Which of these statements are correct? (a) 1, 2 & 3 (b) 1 & 2 only (c) 2 & 3 only (d) 1 & 3 only

Description : Consider the following statements: The time of BOD assimilation in a stream can be affected by 1. Ratio of stream depth to flow width. 2. Stream BOD value 3. BOD rate constant. Which of these statements are correct? (a) 1, 2 & 3 (b) 1 & 2 only (c) 2 & 3 only (d) 1 & 3 only

Last Answer : (a) 1, 2 & 3

Consider the following statements: 1. Organic matter decreases the permeability of a soil. 2. Entrapped air decreases the permeability of a soil. Which of these statements are correct? (a) 1 only (b) 2 only (c) Both 1 &2 (d) Neither 1 nor 2

Description : Consider the following statements: 1. Organic matter decreases the permeability of a soil. 2. Entrapped air decreases the permeability of a soil. Which of these statements are correct? (a) 1 only (b) 2 only (c) Both 1 &2 (d) Neither 1 nor 2

Last Answer : (c) Both 1 &2

Biological Oxygen Demand (BOD) is a measure of: a. Industrial wastes poured into water bodies b. Extent to which water is polluted with organic compounds c. Amount of carbon monoxide inseparably combined with haemoglobin d. Amount of oxygen needed by green plants during night

Description : Biological Oxygen Demand (BOD) is a measure of: a. Industrial wastes poured into water bodies b. Extent to which water is polluted with organic compounds c. Amount of carbon monoxide inseparably combined with haemoglobin d. Amount of oxygen needed by green plants during night

Last Answer : Ans: A

In the activated sludge process A. Aeration is continued till stability B. Aeration is done with an admixture of previously aerated sludge C. Sludge is activated by constant stirring D. Water is removed by centrifugal action

Description : In the activated sludge process A. Aeration is continued till stability B. Aeration is done with an admixture of previously aerated sludge C. Sludge is activated by constant stirring D. Water is removed by centrifugal action

Last Answer : ANS: B

Which one of the following equipments is essentially required for growing microbes on a large scale, for industrial production of enzymes? (a) Bioreactor (b) BOD incubator (c) Sludge digester (d) Industrial oven

Description : Which one of the following equipments is essentially required for growing microbes on a large scale, for industrial production of enzymes? (a) Bioreactor (b) BOD incubator (c) Sludge digester (d) Industrial oven

Last Answer : (a) Bioreactor

Chlorination of water does not remove (A) Ammonia content (B) B.O.D. (C) Organic matter content (D) Dissolved oxygen

Description : Chlorination of water does not remove (A) Ammonia content (B) B.O.D. (C) Organic matter content (D) Dissolved oxygen

Last Answer : (D) Dissolved oxygen

The sewage treatment units in which anaerobic decomposition of organic matter is used, are called A. Imhoff tanks B. Trickling filters C. Sludge sedimentation tanks D. None of these

Description : The sewage treatment units in which anaerobic decomposition of organic matter is used, are called A. Imhoff tanks B. Trickling filters C. Sludge sedimentation tanks D. None of these

Last Answer : ANS: B

Assertion: Amount of biodegradable organic matter present in water is measured by BOD of water Reason: During biodegradation of organic compounds. Oxy

Description : Assertion: Amount of biodegradable organic matter present in water is measured by BOD of water Reason: During biodegradation of organic compounds. Oxy

Last Answer : Assertion: Amount of biodegradable organic matter present in water is measured by BOD of water Reason: ... but reason is wrong D. both are wrong

Measuring Biochemical Oxygen Demand (BOD) is a method used for (a) estimating the amount of organic matter in sewage water (b) working out the efficiency of oil driven automobile engines (c) measuring the activity of Saccharomyces cerevisiae in producing curd on a commercial scale (d) working out the efficiency of RBCs about their capacity to carry oxygen.

Description : Measuring Biochemical Oxygen Demand (BOD) is  a method used for  (a) estimating the amount of organic matter in  sewage water (b) working out the efficiency of oil driven  automobile engines ... commercial  scale (d) working out the efficiency of RBCs about their  capacity to carry oxygen.

Last Answer : (a) estimating the amount of organic matter in  sewage water

High value of BOD (Biochemical Oxygen Demand) indicates that (a) water is less polluted (b) consumption of organic matter in the water is higher by the microbes (c) water is pure (d) water is highly polluted.

Description : High value of BOD (Biochemical Oxygen Demand)  indicates that (a) water is less polluted (b) consumption of organic matter in the water is  higher by the microbes  (c) water is pure (d) water is highly polluted.

Last Answer : (b) consumption of organic matter in the water is 

Measuring Biochemical Oxygen Demand (BOD) is a method used for (a) estimating the amount of organic matter in sewage water (b) working out the efficiency of oil driven automobile engines (c) measuring the activity of Saccharomyces cerevisiae in producing curd on a commercial scale (d) working out the efficiency of RBCs about their capacity to carry oxygen.

Description : Measuring Biochemical Oxygen Demand (BOD) is a method used for (a) estimating the amount of organic matter in sewage water (b) working out the efficiency of oil driven automobile engines (c) ... a commercial scale (d) working out the efficiency of RBCs about their capacity to carry oxygen.

Last Answer : (a) estimating the amount of organic matter in sewage water

High value of BOD (Biochemical Oxygen Demand) indicates that (a) water is less polluted (b) consumption of organic matter in the water is higher by the microbes (c) water is pure (d) water is highly polluted.

Description : High value of BOD (Biochemical Oxygen Demand) indicates that (a) water is less polluted (b) consumption of organic matter in the water is higher by the microbes (c) water is pure (d) water is highly polluted.

Last Answer : (b) consumption of organic matter in the water is higher by the microbes

72. Measuring Biochemical Oxygen Demand (BOD) is a method used for (1) Working out the efficiency of R.B.Cs. about their capacity to carry oxygen (2) Estimating the amount of organic matter is sewage water (3) Working out the efficiency of oil driven automobile engines (4) Measuring the activity of Sacccharomyces cerevisae in producing curd on a commercial scale

Description : 72. Measuring Biochemical Oxygen Demand (BOD) is a method used for (1) Working out the efficiency of R.B.Cs. about their capacity to carry oxygen (2) Estimating the amount of ... driven automobile engines (4) Measuring the activity of Sacccharomyces cerevisae in producing curd on a commercial scale

Last Answer : Estimating the amount of organic matter is sewage water

Which of the following is put into anaerobic sludge digester for further sewage treatment? (a) Primary sludge (b) Floating debris (c) Effluents of primary treatment (d) Activated sludge

Description : Which of the following is put into anaerobic sludge digester for further sewage treatment? (a) Primary sludge (b) Floating debris (c) Effluents of primary treatment (d) Activated sludge

Last Answer : (d) Activated sludge

Assertion : BOD of river polluted by sewage is more than 20 ppm. Reason: Polluted river contains excess of organic matter.

Description : Assertion : BOD of river polluted by sewage is more than 20 ppm. Reason: Polluted river contains excess of organic matter.

Last Answer : Assertion : BOD of river polluted by sewage is more than 20 ppm. Reason: Polluted river contains excess ... true but reason is wrong D. Both are wrong

Biochemical Oxygen Demand (BOD) of sewage is the (a) Oxygen required to oxidise (b) Oxygen required to oxidise biologically inactive organic matter* (c) a and b both (d) none of these

Description : Biochemical Oxygen Demand (BOD) of sewage is the (a) Oxygen required to oxidise (b) Oxygen required to oxidise biologically inactive organic matter* (c) a and b both (d) none of these

Last Answer : (b) Oxygen required to oxidise biologically inactive organic matter*

BOD is connected with a) Organic matter b) microbes c) Microbes and Organic matter d) None of the above.

Description : BOD is connected with a) Organic matter b) microbes c) Microbes and Organic matter d) None of the above.

Last Answer : c) Microbes and Organic matter

(2) amount of oxygen used for biochemical oxidation Explanation: Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. The term also refers to a chemical procedure for determining this amount. This is not a precise quantitative test, although it is widely used as an indication of the organic quality of water.

Description : (2) amount of oxygen used for biochemical oxidation Explanation: Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to ... quantitative test, although it is widely used as an indication of the organic quality of water.

Last Answer : The addition of gypsum to port-land cement helps in : (1) increasing the strength of cement (2) rapid setting of cement (3) preventing rapid setting of cement (4) reduction in the cost of cement

The first stage of neutral process of sludge digestion, is A. Acid fermentation B. Acid regression C. Alkaline fermentation D. None of these

Description : The first stage of neutral process of sludge digestion, is A. Acid fermentation B. Acid regression C. Alkaline fermentation D. None of these

Last Answer : ANS: A

Pick up the correct statement from the following: A. Rate of digestion of sludge is more at higher temperature B. Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C C. Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C D. All the above

Description : Pick up the correct statement from the following: A. Rate of digestion of sludge is more at higher temperature B. Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C C. Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C D. All the above

Last Answer : ANS: D

Lagooning process is mainly a means of the (A) Sludge disposal (B) Reduction of excessive flow in sewers (C) Biological treatment of wastes (D) None of these

Description : Lagooning process is mainly a means of the (A) Sludge disposal (B) Reduction of excessive flow in sewers (C) Biological treatment of wastes (D) None of these

Last Answer : (A) Sludge disposal

What is activated sludge? -Biology

Description : What is activated sludge? -Biology

Last Answer : answer:

For treating the sewage of a large city, you will recommend A. A sedimentation tank and an activated sludge treatment plant B. A plant consisting of Imhoff tanks with low rate trickling filters C. Sedimentation tanks with high rate trickling filters D. None of these

Description : For treating the sewage of a large city, you will recommend A. A sedimentation tank and an activated sludge treatment plant B. A plant consisting of Imhoff tanks with low rate trickling filters C. Sedimentation tanks with high rate trickling filters D. None of these

Last Answer : ANS: A

Activated sludge contains large number of A.bacteria B.yeasts and molds C.protozoa D.all of these

Description : Activated sludge contains large number of A.bacteria B.yeasts and molds C.protozoa D.all of these

Last Answer : D.all of these

Before discharging the foul sewage into rivers, it is generally treated by (a) screening (b) sedimentation (c) Oxidation (d) sludge digestion and disinfection (e) all the above*

Description : Before discharging the foul sewage into rivers, it is generally treated by (a) screening (b) sedimentation (c) Oxidation (d) sludge digestion and disinfection (e) all the above*

Last Answer : e) all the above*

If Organic sources of carcinogenic compounds in water persist even after chlorination, then what is the correct sequence among treatment processes listed below if all these are considered compulsory ? 1. Coagulation 2. Sedimentation 3. Filtration in general 4. Activated carbon bed filtration 5. Flocculation 6. Chlorination a) 4-5-3-2-6 and 1 b) 1-2-3-4-5 and 6 c) 4- 2- 3- 1- 5 and 6 d) 1-5-2-3-4 and 6

Description : If Organic sources of carcinogenic compounds in water persist even after chlorination, then what is the correct sequence among treatment processes listed below if all these are considered compulsory ? 1. Coagulation 2. Sedimentation 3. Filtration in ... c) 4- 2- 3- 1- 5 and 6 d) 1-5-2-3-4 and 6

Last Answer : d) 1-5-2-3-4 and 6

During anaerobic digestion of organic waste, such as in producing biogas, which one of the following is left undegraded? (a) Lipids (b) Lignin (c) Hemi-cellulose (d) Cellulose

Description : During anaerobic digestion of organic waste, such as in producing biogas, which one of the following is left undegraded? (a) Lipids (b) Lignin (c) Hemi-cellulose (d) Cellulose

Last Answer : (b) Lignin

The biological process in which both aerobes and anaerobes degrade organic matter is - (1) Manuring (2) Composting (3) Digesting (4) Nitrifying

Description : The biological process in which both aerobes and anaerobes degrade organic matter is - (1) Manuring (2) Composting (3) Digesting (4) Nitrifying

Last Answer : (2) Composting Explanation: Composting is the depomposition of plant remains and other once-living materials to make an earthy, dark, crumbly substance that is excellent for enriching soil. It is the chief way to recycle wastes.

The biological process in which both aerobes and anaerobes degrade organic matter is (1) Manuring (2) Composting (3) Digesting (4) Nitrifying

Description : The biological process in which both aerobes and anaerobes degrade organic matter is (1) Manuring (2) Composting (3) Digesting (4) Nitrifying

Last Answer : Composting

Consider the following statements. The role of the gravel bed in a rapid sand filter is : 1. To filter out large suspended matter 2. To support the sand bed above it 3. To prevent the escape of sand particles 4. To uniformly distribute the backwash water 5. To prevent algae growth Which of the following statements are correct ? a) 1, 2, 3, 4 and 5 b) 2, 3 and 4 only c) 3, 4 and 5 only d) 1, 2 and 3 only

Description : Consider the following statements. The role of the gravel bed in a rapid sand filter is : 1. To filter out large suspended matter 2. To support the sand bed above it 3. To prevent the escape of sand particles 4. To uniformly ... and 5 b) 2, 3 and 4 only c) 3, 4 and 5 only d) 1, 2 and 3 only

Last Answer : b) 2, 3 and 4 only

Lagoons used for purification of polluted water (A) Are large shallow artificial lakes also known as clarification lakes, maturation ponds or oxidation ponds (B) Use micro-organisms/bacteria in presence of dissolved oxygen (C) Gives an excellent final effluent (with 3 to 4 lagoons arranged in series) having suspended solid < 1 mg/litre and BOD = 3.8 mg/litre (D) All (A), (B) & (C)

Description : Lagoons used for purification of polluted water (A) Are large shallow artificial lakes also known as clarification lakes, maturation ponds or oxidation ponds (B) Use micro-organisms/bacteria in presence of dissolved oxygen (C) Gives an ... 1 mg/litre and BOD = 3.8 mg/litre (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Agglomeration of individual particles into clusters (flocs) is called flocculation. To prevent flocculation, the most commonly used dispersing agents are (A) Carbonates (B) Sulphates (C) Silicates & phosphates (D) Bi-carbonates

Description : Agglomeration of individual particles into clusters (flocs) is called flocculation. To prevent flocculation, the most commonly used dispersing agents are (A) Carbonates (B) Sulphates (C) Silicates & phosphates (D) Bi-carbonates

Last Answer : (C) Silicates & phosphates

Q No: 251 In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is A. [(100 + P1)/(100 – P2)] V1 B. [(100 – P1)/(100 + P2)] V1 C. [(100 – P1)/(100 – P2)] V1 D. [(100 + P2)/(100 – P1)] V1

Description : Q No: 251 In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is A. [(100 + P1)/(100 – P2)] V1 B. [(100 – P1)/(100 + P2)] V1 C. [(100 – P1)/(100 – P2)] V1 D. [(100 + P2)/(100 – P1)] V1

Last Answer : ANS: C

In normal conditions, the period for sludge digestion, is A. 10 days B. 20 days C. 30 days D. 60 days

Description : In normal conditions, the period for sludge digestion, is A. 10 days B. 20 days C. 30 days D. 60 days

Last Answer : ANS: C

The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is A. 25 % B. 50 % C. 10 % D. 5 %

Description : The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is A. 25 % B. 50 % C. 10 % D. 5 %

Last Answer : ANS: B

11. Acid regression stage of sludge digestion at a temperature 21°C extends over a period of A. 15 days B. 30 days C. 60 days D. 90 days

Description : 11. Acid regression stage of sludge digestion at a temperature 21°C extends over a period of A. 15 days B. 30 days C. 60 days D. 90 days

Last Answer : ANS: D

The principal gas evolved from sludge digestion tank is (A) CO(B) CO2 (C) CH4 (D) N2

Description : The principal gas evolved from sludge digestion tank is (A) CO (B) CO2 (C) CH4 (D) N2

Last Answer : (C) CH4

If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l

Description : If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l

Last Answer : ANS: D

The domestic sewage in large cities (a) has a high BOD as it contains both aerobic and anaerobic bacteria (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs) (c) when treated in STPs does not really require the aeration step as the sewage contains adequate oxygen (d) has very high amount of suspended solids and dissolved salts.

Description : The domestic sewage in large cities (a) has a high BOD as it contains both aerobic and anaerobic bacteria (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in ... sewage contains adequate oxygen (d) has very high amount of suspended solids and dissolved salts.

Last Answer : (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs)

Which is the most practical and economical method for removal of suspended solid matter from polluted water? (A) Sedimentation (B) Skimming off (C) Chlorination (D) Biological oxidation

Description : Which is the most practical and economical method for removal of suspended solid matter from polluted water? (A) Sedimentation (B) Skimming off (C) Chlorination (D) Biological oxidation

Last Answer : (A) Sedimentation

In the context of the chemical process industries, the term BOD is normally associated with the (A) Characterisation of solid wastes (B) Organic concentration in gaseous effluents (C) Characterisation of liquid effluents (D) Characterisation of boiler feed water

Description : In the context of the chemical process industries, the term BOD is normally associated with the (A) Characterisation of solid wastes (B) Organic concentration in gaseous effluents (C) Characterisation of liquid effluents (D) Characterisation of boiler feed water

Last Answer : (C) Characterisation of liquid effluents

Which one of the following is not a matter a global concern in the removal of tropical forests ? (A) Their ability to absorb the chemicals that contribute to depletion of ozone layer. (B) Their role in maintaining the oxygen and carbon balance of the earth. (C) Their ability to regulate surface and air temperatures, moisture content and reflectivity. (D) Their contribution to the biological diversity of the planet.

Description : Which one of the following is not a matter a global concern in the removal of tropical forests ? (A) Their ability to absorb the chemicals that contribute to depletion of ozone layer ... , moisture content and reflectivity. (D) Their contribution to the biological diversity of the planet.

Last Answer : (A) Their ability to absorb the chemicals that contribute to depletion of ozone layer.