Tag: human influences on the environment

Questions Related to human influences on the environment

What is relative contribution of $CO _2, CH _4$, CFC and $N _2O$ to global warming?

zoology human influences on the environment carbon cycle ozone layer depletion and causes depletion of ozone layer

  1. $20\%, 14\%, 60\%, 6\%$

  2. $14\%, 6\%, 20\%, 60\%$

  3. $60\%, 20\%, 14\%, 6\%$

  4. $6\%, 14\%, 20\%, 60\%$

  5. $20\%, 60\%, 14\%, 6\%$

Show answer
Correct Option: C
Explanation:

Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere up to a specific time horizon, relative to carbon dioxide. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide and is expressed as a factor of carbon dioxide an index of global warming potential for methane, carbon monoxide, nitrous oxide and CFCs relative to that of carbon dioxide. The major contribution is from CO$ _2$ (60%),CH$ _4$ (20%), CFC and N$ _2$O attributes to 14% and 6% respectively.

So the correct answer is '60%,20%,14%,6%'.

BOD is ___________ in polluted water and ________in potable water.

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

  1. more, less

  2. less, more

  3. less in both

  4. medium in both

Show answer
Correct Option: A
Explanation:
A low BOD is an  indicator of good quality of water. Whereas a high BOD indicates polluted water as in that water the dissolved oxygen is consumed by bacteria.
So, the correct option is 'more, less'

BOD of wastewater is amount of

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

  1. total organic matter

  2. biodegradable organic matter

  3. oxygen evolution

  4. oxygen consumption

Show answer
Correct Option: D
Explanation:

biological oxygen demand is the amount of Oxygen required by aerobic micro-organisms for the breakdown of organic matter present in waste water or polluted water.

So, the correct answer is 'oxygen consumption'

If a water body have high amount of DDT it's 'Biochemical Oxygen Demand' (B.O.D.) will

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

  1. Decrease

  2. Not affected

  3. Increase

  4. First decrease than increase

Show answer
Correct Option: C
Explanation:

Biological Oxygen Demand (BOD) is one of the most common measures of pollutant organic material in water. BOD indicates the amount of putrescible organic matter present in water. Therefore, a low BOD is an indicator of good quality water, while a high BOD indicates polluted water. When BOD levels are high, dissolved oxygen (DO) levels decrease because the oxygen that is available in the water is being consumed by the bacteria. Since less dissolved oxygen is available in the water, fish and other aquatic organisms may not survive.


So, the correct option is 'Increase'.

The enhanced growth of water hyacinth in lakes can be due to

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

  1. Disposal of solid wastes in water bodies

  2. Availability of more nutrients to the flora of a water ecosystem

  3. Discharge of sewage into water bodies

  4. All of the above

Show answer
Correct Option: D
Explanation:

Water hyacinth (Eichhornia crassipes) also known as Bengal terror is waterweed often blamed for choking water bodies and creating problems for aquatic plants and animal due to less availability of oxygen. It mainly grows where organic nutrient is present in large amount. Level of the nutrient increase due to use of pesticide, weedicides, of discharge of sewage into the water bodies. 

So, the correct option is 'all of the above'.

BOD of lake becomes high by :-

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

  1. Vehicles

  2. Wind mill

  3. Smoke and ammonia

  4. Detergents

Show answer
Correct Option: D
Explanation:
BOD or biological oxygen demand is the amount of water needed by aerobic organisms to break down the organic substances (waste substances) present in a water body. Detergents reduce the amount of oxygen in a water body. This may result in an increase in the BOD. It may also result in an increase in eutrophication in the water bodies. Vehicles, wind mill, and smoke and ammonia on the other hand act mostly as air pollutants and are responsible for air pollution.
So, the correct answer is 'Detergents'.

Primary treatment reduces BOD, ranges from;

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

  1. 30-60%

  2. 0-70%

  3. 30-35%

  4. 20-80%

Show answer
Correct Option: C

Composition of sewage water depends on its

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

  1. Nutrient

  2. Sources

  3. Water content

  4. Sunlight

Show answer
Correct Option: B

How much BOD reduces in preliminary treatment?

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

  1. 15 to 30%

  2. 17 to 60%

  3. 19 to 80%

  4. 10 to 90%

Show answer
Correct Option: A

If the river water is polluted with domestic sewage and garbage, it leads to the depletion of 

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

  1. CO$ _2$

  2. CO

  3. O$ _2$

  4. All of the above

Show answer
Correct Option: C
Explanation:

A lake rich in domestic sewage and garbage nutrients will leads to eutrophication. Eutrophication is when the environment becomes enriched with nutrients. This can be a problem in aquatic habitats such as lakes as it can cause algal blooms and other aquatic plants. Following this, overcrowding occurs and plants compete for sunlight, space and oxygen. It deoxygenate the water enough to kill the fish and other animals. Thus, the correct answer is option C.