|
What are fossils? How are fossils formed and how is their age determined?
|
|
1
|
559
|
April 4, 2019
|
|
Explain the harmful effects of ozone depletion on Earth
|
|
1
|
571
|
April 4, 2019
|
|
(a) Why should ozone layer be protected to save the environment?
|
|
1
|
5379
|
April 4, 2019
|
|
Give reason to justify the following: (a) The existence of decomposers is essential in a biosphere
|
|
1
|
5843
|
April 4, 2019
|
|
“Energy flow in a food chain is unidirectional. Justify this statement
|
|
1
|
1113
|
April 4, 2019
|
|
“Our food grains such as wheat and rice, the vegetables and fruits
|
|
1
|
1051
|
April 4, 2019
|
|
(a) What is an ecosystem? List its two main components
|
|
1
|
1107
|
April 4, 2019
|
|
How is ozone formed in the higher level of atmosphere?
|
|
1
|
2869
|
April 4, 2019
|
|
What is “Green House Effect”? State two advantages and two disadvantage of this effect
|
|
1
|
624
|
April 4, 2019
|
|
“Reuse is better than recycling of materials”. Give reason to justify this statement
|
|
1
|
1649
|
April 4, 2019
|
|
List two reasons to show that the existence of decomposers is essential in an ecosystem
|
|
1
|
2538
|
April 4, 2019
|
|
Why is Government of India imposing a ban on the use of polythene bags?
|
|
1
|
939
|
April 4, 2019
|
|
List the products of combustion of fossil fuels ? What are their adverse effects on the environment?
|
|
1
|
785
|
April 4, 2019
|
|
An environmentalist on visit to your school suggested the use of three R’s to save the environment
|
|
1
|
2477
|
April 4, 2019
|
|
How are the following caused and what is the effect of each of them on our environment? (i) Depletion of ozone layer (ii) Acid rain
|
|
1
|
670
|
April 4, 2019
|
|
List any four practices which help in protecting our environment
|
|
1
|
1186
|
April 4, 2019
|
|
Why is conservation of wildlife considered important for us? Give any two reasons
|
|
1
|
992
|
April 4, 2019
|
|
What is acid rain? Mention its two harmful effects
|
|
1
|
1293
|
April 4, 2019
|
|
Distinguish between biodegradable and non-biodegradable wastes. Give one example of each
|
|
1
|
593
|
April 4, 2019
|
|
How does depletion of soil takes place? Suggest two ways to prevent it
|
|
1
|
605
|
April 4, 2019
|
|
Describe how green house effect may cause atmospheric heating?
|
|
1
|
547
|
April 4, 2019
|
|
Waste of which of the following two materials in more polluting? Polythene or paper. Give reasons for your answer
|
|
1
|
1438
|
April 4, 2019
|
|
Write one negative effect, on the environment of affluent lifestyle of few persons of a society?
|
|
1
|
971
|
April 4, 2019
|
|
The depletion of ozone layer is a cause of concern why?
|
|
1
|
1937
|
April 4, 2019
|
|
Why should biodegradable and non-biodegradable wastes be discarded in two separate dust bins?
|
|
1
|
1128
|
April 4, 2019
|