Tag: human influences on the environment

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Questions Related to human influences on the environment

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

BOD of a pond is related to .......... in per unit volume of water.

  1. All the plants

  2. All the nektons

  3. All the microbes

  4. All the animals
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic microorganisms to break down organic material present in a given water sample at certain temperature over a specific period of time. Thus, the correct answer is option C.

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

BOD is related to

  1. Organic pollutants

  2. Detergents

  3. Putrescibility

  4. Inorganic pollutants
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

BOD is abbreviated form of biological oxygen demand. It is the amount of oxygen required by microbes to break down the organic matter present in a certain volume of a sample of water. The amount of BOD in the water is a measure of a number of organic pollutants in the water.

Thus, the correct answer is option A. 

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

High BOD values for a river means that river water

  1. Have no microbes

  2. Have more bacteria

  3. Is highly polluted

  4. Is highly clean
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Biochemical Oxygen Demand (BOD) measures the amount of oxygen required by aerobic microorganisms to decompose organic matter. High BOD indicates a high concentration of organic pollutants in the water.

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

C.O.D. stands for

  1. Chemical oxygen demand

  2. Control of diesel

  3. Csiumoxide deposition

  4. Cemistry of depositions
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

C.O.D. stands for chemical oxygen demand. It is the measurement of the pollution which is based on the chemical decomposition of organic and oxidation of the inorganic contaminants present in dissolved water. It is mainly used against waste water which is contaminated by domestic and industrial wastes.

So, the correct answer is option A.

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

In the polluted water, the values of

  1. C.O.D. slightly higher than B.O.D.

  2. C.O.D. much higher than B.O.D.

  3. B.O.D. slightly higher than C.O.D.

  4. B.O.D. much higher than C.O.D.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chemical Oxygen Demand (COD) measures the total amount of oxygen required to chemically oxidize all organic matter, whereas BOD only measures biodegradable organic matter. Therefore, COD is almost always higher than BOD.

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

When huge amount of CO$ _2$ is dumped into a river, the BOD will

  1. Increase

  2. Slightly decrease

  3. Remain unchanged

  4. Decrease
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Biological Oxygen Demand is a measurement of the amount of dissolved oxygen that is used by aerobic microorganisms when decomposing organic matter in water.  It is expressed in milligrams of oxygen consumed per liter of the sample during 5 days of incubation at 20°C and is used to determine the degree of organic pollution of water. Hence when a huge amount of carbon dioxide is added BOD will not be affected. Thus, the correct answer is option C.

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

A rapid growth of photosynthetic algae in water develops 'bloom'. How would it affect the environment of water?

  1. The environment becomes comfortable for all forms of life.
  2. O$ _2$ level is decreased or BOD becomes high.
  3. O$ _2$ level of water is increased.

  4. Fish production is increased.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Algal blooms lead to excessive organic matter. As this matter decomposes, aerobic bacteria consume dissolved oxygen, leading to a decrease in O2 levels and an increase in BOD, which harms aquatic life.

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

For how long and at what temperature an experiment is run to determine the value of BOD of a water body? 

  1. $10^oC$ for 10 days
  2. $20^oC$ for 5 days
  3. $20^oC$ for 2 days
  4. $5^oC$ for 20 days
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

BOD or biochemical oxygen demand is the amount of dissolved oxygen which is required by the aerobic organisms during the decomposition of organic matter. The BOD is measured at a specific temperature and specific period of time. BOD value is represented in the form of oxygen which is consumed per litre of the sample used for testing. The sample is tested before and after 5 days of incubation at 20 °C. The value describes the amount of organic material present in the contaminated or waste water. 

Thus, the correct answer is option B. 

Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

Which of the following enhances B.O.D. of water ?

  1. Sugar mill effluents

  2. Algae

  3. Sand

  4. Moss
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
B.O.D. or Biochemical oxygen demand is the amount of dissolved oxygen which is required by the aerobic organisms during the decomposition of organic matter. It is measured at a specific temperature and specific period of time. The wastes from the sugar mill effluents are directly poured into the water bodies which enhances the demand of required oxygen to completely oxidize the organic compounds to carbon dioxide which leads to overall increase in biochemical oxygen demand.
Thus, the correct answer is option A.
Multiple choice biology human influences on the environment effects of water pollution effect of water pollution water pollution and its control

The measurement of rate of oxygen utilisation by a unit volume of water over a period of time is to measure.

  1. Biochemical oxygen demand

  2. Biosynthetic path

  3. Biogas generation

  4. Fermentation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

BOD or Biochemical oxygen demand is the amount of dissolved oxygen which is required by the aerobic organisms during the decomposition of organic matter. The BOD is measured at a specific temperature and specific period of time. BOD value is represented in the form of oxygen which is consumed per litre of the sample used for testing. The sample is tested before and after 5 days of incubation at 20 °C. The value describes the amount of organic material present in the contaminated or waste water. 

Thus, the correct answer is option A.