Pollution is an undesirable change in physical, chemical and biological characteristics of environment, air, water, soil and land that has potential to adversely affect human life, the lives of the desirable species, natural resources, industrial processes and cultural assets.
Given below are the sources of pollution and their effects. Using this information fill the spaces in the given box. Each pollutant may have more than one source and may show more than one effect.
Pollutant source: Automobile exhaust, burning of fossils, refrigerant, agricultural field, fire extinguisher, paint solvents, deforestation, plastic foam.
Effect: Photochemical smog, acid deposition, global warming, depletion of ozone.

"To reduce or check the global warming is the biggest challenge. Scientist belive that this rise in temperature is leading to deletrious changes in environment and resulting in odd climates".
(i) Write one difference between E1-nino and La-nino affect.
(ii) Name any two agents which cause global warming.

One day, Hari asked his uncle why can not he clear various types of wild plants in the vicinity of his village and use the land for cultivation of crops? Uncle replied that it will not be a wise step as plants other than crops are also essential for our survival.
Read the above passage and answer the following question :
(i) As a student of biology, in your opinion who is right Hari or His uncle and why ?
(ii) What is the term used to denote the diversity among living things?
(iii) What are the benefits of biodiversity?

While visiting a national park, Ravi noticed a board with warning that hunting and killing of wild animals is a punishable crime. He failed to understand why killing a wild animal who may harm human beings, is a crime? He discussed it with his biology teacher who made him realise the importance of wild life for human survival.
Read the above passage and answer the following questions:
(i) How is our survival linked with the existence of wild animals?
(ii) How can we protect these animals?
(iii) What value is displayed by Ravi's teacher ?

Satish heard about red data book in a TV programme on conservation of natural resources. He wanted to know in detail about this book so he discussed it with biology teacher who explained to him about this.
Read the above passage and answer the following questions:
(i) What is Red Data Book?
(ii) What is the utility of this document?
(iii) Who publishes this book?