If UNEP had not passed any regulation to control the CFC levels, then what could have been the possible consequences after a few years?
Increase in CFC levels and thus increase in global warming.
Major amount of UV radiations reaching the earth, therefore, multifold increase in problems like cancer.
Increase in natural calamities like Tsunamis and cyclones.
Lowering of the temperature of the earth.
(2)
If UNEP has not controlled the CFC levels, then after 20 years there would have been major destruction of the ozone layer due to an increase in CFC levels in the environment.
Which of the following sets represents the substances required for the formation of ozone?
Oxygen and IR radiations
Oxygen and UV radiations
Oxygen and radiations of longer wavelengths
Carbon dioxide, water vapour and UV radiations
(2)
Ozone is formed by the action of UV radiations on the oxygen atoms in the upper layers of the atmosphere.
Which of the following options complete the statement given below?
Ozone is both harmful and beneficial because it is __________.
not poisonous to the ecosystem
poisonous but not for humans
poisonous in very high amounts, and its concentration is very low in the atmosphere
poisonous to humans but it also prevents UV rays from entering into the earth’s atmosphere
(4)
Ozone acts as a blanket around the earth and prevents the UV rays from entering the earth’s atmosphere. However, at the surface level, it acts as a pollutant.
Ozone formation is possible in the upper layers of atmosphere because of the:
presence of active molecules of carbon
presence of high energy UV rays
presence of activated oxides of carbon
presence of longer wavelength radiations
(2)
The high energy of UV rays help in the formation of ozone from oxygen.
Which of the following is the set of greenhouse gases in the atmosphere?
Ozone and CFC
Carbon monoxide and sulphur dioxide
Carbon dioxide and methane
Hydrogen sulphide and ozone
(3)
Gases that maintain the temperature of the earth by trapping the solar energy in the earth’s atmosphere are called greenhouse gases. Increase in the amount of greenhouse gases in the atmosphere can lead to global warming. Carbon dioxide and methane are the greenhouse gases.
Refrigerators have led to an environmental imbalance and destroyed ecosystems. How?
Refrigerators emit CFCs that are harmful to only plant species.
Storing food in refrigerators makes them environmentally unhealthy.
Refrigerators use CFCs that are harmful to the ozone layer which forms a blanket around the earth.
Refrigerators emit greenhouse gases.
(3)
CFCs are used in refrigerators. They are dangerous for the ozone layer that acts as a blanket around the earth and prevents UV rays from the sun to enter the atmosphere.
Classify the given activities under reuse and recycle.
(i) Using plastic bucket for growing plants
(ii) Using old newspaper to make paper bags
(iii) Using broken glass to melt and make a new glass
(iv) Dissolving paper, bleaching and drying it to form a new paper.
(i) and (ii) are examples of reuse and (iii) and (iv) are the examples of recycle.
(ii) and (iii) are the examples of reuse and (i) and (iv) are the examples of recycle.
(i), (ii) and (iii) are the examples of reuse and (iv) is the example of recycle.
(i), (ii) and (iii) are the examples of recycle and (iv) is the example of reuse.
(1)
Reuse involves using again the same substance for some other purpose. Recycle involves forming a new substance from the old substance to be used for the same or different purpose.
Different types of enzymes are present in our body because:
(i) each enzyme has a specific function
(ii) each enzyme has a specific substrate
(iii) it makes the metabolic process faster
(iv) it makes the replacement of the defective enzymes easy
(i) and (ii)
(iii) and (iv)
(i) and (iv)
All of these
(1)
Each enzyme has a specific substrate and has a specific function to perform. Each enzyme is a protein and each protein is made by a specific gene.
Disposable plastic plates should not be used because :
they are made of materials with light weight.
they are made of toxic materials.
they are made of biodegradable materials.
they are made of non-biodegradable materials.
(4)
There are some substances that cannot be acted upon by decomposers and hence, these items are called as non-biodegradable. Examples: plastics, chemicals like DDT, etc. When items like disposable plastic plates are used they persist in the environment because they cannot be degraded and may cause hazardous effects on the other biotic components of the ecosystem. Therefore, usage of disposable plastic should be avoided as they have hazardous effects on the environment.
Some wastes stay in the environment for a longer duration because:
they are non-biodegradable materials and decomposers cannot decompose them.
they are biodegradable materials but decomposers do not act on these materials.
these play role in maintaining ecological balance
these are recyclable.
(1)
Some waste materials are non-biodegradable. Decomposers cannot break them into simpler forms. Therefore, these materials stay in the environment for a longer duration.
