Short Answer Type Questions
Q.1. Prepare a list of five items that you use daily in the school. Identify from the list such items that can be recycled.
Ans. Paper, pen, pencil, eraser, scale, plastic box, stainless steel lunch box, stainless steel spoon, steel compass, steel dividers, handkerchief.
Recyclable items: Stainless steel lunch box, stainless steel spoon, steel compass, steel dividers, paper, plastic box, eraser.
Q.2. List two advantages associated with water harvesting at the community level.
Ans. Two advantages of water harvesting at the community level:
(a) Water can be stored during rainy season and can be used when required.
(b) Groundwater level increases due to recharging of wells.
Q.3. In a village in Karnataka, people started cultivating crops all around a lake which was always filled with water. They added fertilisers to their field in order to enhance the yield. Soon they discovered that the waterbody was completely covered with green floating plants and fishes started dying in large numbers.
Analyse the situation and give reasons for excessive growth of plants and death of fish in the lake.
Ans. Because of the excessive use of fertilisers in the fields, they were carried down to the lake during rains. The fertilisers contain phosphates and nitrates, resulting in excessive growth of algae and other aquatic plants which float on water surface. The submerged plants are killed due to shading and insufficient availability of dissolved oxygen, resulted in the death of fish in the lake.
Q.4. What measures would you take to conserve electricity in your house?
Ans. (a) Switching off lights and fans when not required.
(b) Use of solar radiation for cooking food and lighting.
(c) Use of fluorescent tubes or LED.
(d) Use of solar water heating system during winters.
Q.5. Although coal and petroleum are produced by degradation of biomass, yet we need to conserve them. Why?
Ans. Coal and petroleum are rich source of energy and take millions of years for their formation. As these resources are being consumed in ever increasing amount in industry, transport, kitchen, etc, these are utilised at a much faster rate than their formation, and will get exhausted. Therefore, they must be conserved.
Q.6. Suggest a few measures for controlling carbon dioxide levels in the atmosphere.
Ans. (a) Planting more trees
(b) Reduce the consumption of petrol and diesel in automobiles.
(c) Use of CNG.
(d) Instead of burning litter, manure can be prepared.
(e) Treatment of smoke to remove harmful gases before discharging into atmosphere.
Q.7. (a) Locate and name the water reservoirs in figures (a) and (b).
(b) Which has an advantage over the other and why?
Ans. (a) Water reservoir in Fig (a) is pond while in Fig (b) it is underground water body.
(b) Fig (b) Groundwater has more advantage than pond water some of which are:
(i) It spreads out to recharge wells.
(ii) It provides moisture for vegetation over a wide area.
(iii) It does not evaporate.
(iv) It does not allow breeding of insects.
(v) It is protected from contamination by animal and human wastes.
Q.8. Prepare a list of five activities that you perform daily in which natural resources can be conserved or energy utilisation can be minimised.
Ans. (a) To close all taps after use.
(b) Use of LED in place of conventional bulbs/ tubes.
(c) Use of fans and lights only when required.
(d) Washing vehicles only when dirty
(e) Water used for washing vegetables and fruits can be used for watering plants.
Long Answer Type Questions
Q.9. Is water conservation necessary? Give reasons.
Ans. Yes, water conservation is necessary because:
(a) Water distribution is uneven and large tracts are deficient in rain as well as groundwater.
(b) Requirement of water in urban and industrial areas is higher than its availability.
(c) The demand of water is rising in various fields of agriculture or domestic use.
(d) At most places more water is withdrawn from reservoir and underground source than their recharging.
(e) Water is necessary to generate electricity throughout the year.
(f) Many other food items like fishes are obtained from water bodies.
Q.10. Suggest a few useful ways of utilising waste water.
Ans. Ways to utilise waste water:
(a) It can be used for irrigation.
(b) The water used for washing fruits and vegetables can be used for watering gardens and washing cars.
(c) Industries can treat their waste water and recycle the same.
(d) Sludge separated from sewage (which is a type of waste water). This waste water can be a source of manure, compost and biogas.
Q.11. What is the importance of forest as a resource?
Ans. Importance of forest as a resource:
(a) It helps in maintaining balance of CO2 and O2 in the atmosphere.
(b) It improves water holding capacity of soil.
(c) It regulates water cycle
(d) It serves all essential commodities like fuel wood, timber pulp and paper for human beings.
(e) It also provides useful products like fruits, gums, resins, essential oils, etc.
(f) Forest is the; habitat and provides food and protects the wildlife species.
Q.12. Why are the Arabari forests of Bengal known to be a good example of conserved forest?
Ans. The Arabari forests of Bengal are known to be a good example of conserved forest. A strategy was developed by forest department in which the villagers were involved in the protection of foreists. In return, the villagers were paid and given some’ benefit in harvesting operations. They were allowed to collect wood and fodder on payment of nominal fee. Therefore, the sal forests of this region were conserved by the active participation of the local people.