Very Short Answer Questions - 1 Mark

Que 1. Why is it necessary to conserve our environment? 

Ans. It is necessary to conserve our environment in order to maintain ecological balance. 

Que 2. Name any two biodegradable and two non biodegradable pollutants. 

Ans. Biodegradable: domestic sewage and wood. Non Biodegradable: Plastic and DDT 

Que 3. we often use the word environment. What does it mean? 

Ans. Environment is the physical, chemical and biological conditions of the region. 

Que 4. Which two of the following are biodegradable? 

            Tomato leaves, aluminium wire, synthetic fibre and wool 

Ans. Tomato leaves and wool. 

Que 5. Which of the following are non-biodegradable? 

            Wool, glass, silver foil and leather. 

Ans. Glass and silver foil. 

Que 6. What is the function of ozone in the upper atmosphere? 

Ans. Ozone shields the surface of the earth from ultraviolet rays from the Sun. 

Que 7. Why should biodegradable and non-biodegradable wastes be discarded in two separate dustbins?  

Ans. Biodegradable and non-biodegradable wastes should be discarded in two separate dustbins so that the time and energy required in segregation may be saved and waste may be disposed off quickly. 

Que 8. What are the two main components of our environment?  

Ans. The two components are biotic or living and abiotic or non-living component. 

Q. 9. List two biotic components of a biosphere. 

Ans. Producers, consumers and decomposers are the biotic components of a biosphere. (Any one)

Que 10. Name any two abiotic components of an environment.  

Ans. Abiotic components of an environment include soil and water. 

Que 11. Name two decomposers. 

Ans. Bacteria and fungi. 

Que 12. Write an aquatic food chain. 

Ans.  

Que 13. What will be the amount of energy available to the organisms of the 2nd trophic level of a food chain, if the energy available at the first trophic level is 10,000 joules?  

Ans. On applying the 10% law to the food chain the organisms of the 2nd trophic level of the food chain will have  

Que 14. Draw a food chain with four trophic levels. 

Ans. Plants→ Rats → Snakes→ Hawks

Que 15. The first trophic level in a food chain is always a green plant. Why? 

                                                                        Or  

Why do producers always occupy the first trophic level on every food chain? 

Ans. The first trophic level is always a green plant because only plants can utilise the radiant energy of the sun and transform it to chemical form during photosynthesis.

Que 16. Which of the following are always at the second trophic level of food chains? 

              Carnivores, Autotrophs, Herbivores 

Ans. Herbivores are always at the second trophic level of food chains. 

Que 17. The following organisms form a food chain. Which of these will have the highest concentration of non-biodegradable chemicals? Name the phenomenon associated with it.

              Insects, Hawk, Grass, Snake, Frog. 

Ans. Hawk will have the highest concentration of non-biodegradable chemicals.  

The phenomenon associated is biomagnification. 

Que 18. Write the full name of the group of compounds mainly responsible for the depletion of ozone layer.

Ans. Chlorofluorocarbons

Que 19. List two examples of natural ecosystem.

Ans. Forests, ponds, lakes are examples of natural ecosystem.

Que 20. Why are green plants called producers?

Ans. Green plants are called producers because they prepare food by photosynthesis using solar energy. 

Que 21. List four common waste disposal methods.

Ans. Compost, recycling of wastes, landfills and incineration. 

Que 22. What is incineration? 

Ans. Incineration means ‘reducing to ashes’. The burning of substances at high temperature to forms ash is called incineration.

Que 23. Why is improper disposal of waste a curse to environment? 

Ans. Wastes pollute our environment, air, soil and water, and cause harmful effects on all living organisms.

Que 24. The depletion of ozone layer is a cause of concern. Why? 

Ans. Ozone layer is very important for the existence of life on earth because it prevents harmful ultraviolet (U V) radiations coming from the Sun to reach the earth.

Que 25. What destructive effect do chlorofluorocarbons bring about in the atmosphere? 

Ans. CFCs deplete ozone from ozone shield, resulting in increasing the passage of harmfal ultraviolet radiation to the earth. 

Que 26. Write one negative effect, on the environment, of affluent life style of few persons of a society.

Ans. Affluent lifestyle results in: 

(i) generation of excessive waste materials.  

(ii) Excessive use of natural resources like coal and petroleum which causes pollution. 

(iii) Use of excessive non biodegradable material in packaging.     (Any one)