Questions from Recent CBSE Board paper Q. How does concentration of a pesticide change once it enters a food chain.
Ans: Concentration of a pesticide increases once it enters a food chain.
Q. In an ecosystem, rats feed on grains. Name the trophic level to which the rats belong.
Ans: Second trophic level
Q. What will be the consequences if all the carbon of all fossil fuel is converted into carbon dioxide ?
Ans: Amount of carbon dioxide in the atmosphere will increase leading to global warming.
Q. If all the wastes we generate is biodegradable, what effect will this have on the environment ? What value will be imbibed if people are made to understand that generation of waste should be restricted to be biodegradable only ?
Ans: (a) It will lead to eco friendly environment, waste product would be converted into re-usable form.
(b) Mutual respect to health and environment conservation.
Q. In a colony, it was decided to remove a green park and construct an air conditioned shopping mall. Children of the colony took out a march against this decision with several placards to make the colony people aware of the importance of green plants.
a. What are the ill effects of air conditioners? b. Design two placards which the children would have carried? c. Is the action taken by the children justified? d. How does the ecosystem get affected when plants are removed?
Ans: a. They release CFCs that deplete ozone layer.
b. Green plants are our green lungs and water purifying systems.
c. Yes, they are trying to protect the environment.
d. Food chain is disrupted and drastic climatic changes occur. Major part of biota is lost.
Q. In a food chain comprising frogs, insects, birds and grass, which one of the organisms is likely to have maximum concentration of harmful non biodegradable chemicals in its body?
Chapter : Our Environment :- Value Based Questions with Solution
Q . It is often advised to stop our vehicles engine at red light and also to drive car / vehicles at constant speed.
Based on the above statement, answer the following question.
1. Which type of fuel is used in vehicles? Is it renewable or non renewable. 2. How can you contribute towards saving these fuels at your level?
Ans: Fossil fuel – non renewable
=> Traveling in Metro (MRTS) / Public transport
=> Opting for CNG as a motor fuel instead of petrol & diesel.
Associated Value : The learners will adopt all these fuel saving techniques in their life.
Q . Number of vultures is decreasing remarkably. Now days which is a matter of concern.
1. Vultures belong to which category of animal. 2. What is their role in nature to maintain ecological balance.
Ans: i. Scavenger ii. Help in recycling in nature by eating dead animals.
Associated Value : The learners will be able to understand and participate in maintaining ecological Balance by not harming other creatures
Q . Newspaper reports about the alarming increase in pesticides level in packed food items Some of states have even banned these food items.
1. What are the sources of these pesticides in these food items. 2. Name the biological phenomenon associated with accumulation of pesticide in the food chain.
Ans: 1. Chemicals (Pesticides, Fertilizers) used in agricultural practices. 2. Biological magnification.
Associated Value : The learners will be able to apply rational approach while using such pesticides and will be more careful towards using packaged food.
Q . Ozone depletion / Ozone hole is a cause of concern now a days. 1. What are the causes of ozone depletion. 2. As students what steps will you advise to reduce ozone depletion.
Ans: 1. Chlorofluoro carbon (CFCs) released into atmosphere disintegrate the ozone molecule.
2. Stop using devices that release CFCs.
Associated Value : The learners will be more educated and will be more vigilant & judicious towards using equipments /chemical that produces CFCs in order to protect ozone layer.
Q . Acid rain is causing damage to monuments / Buildings etc. and also harm the flora and fauna.
1. What is the cause of acid rain. 2. What essential changes in our daily life can lie done to prevent acid rain / damage caused by acid rain.
Ans: 1. Oxides of Nitrogen & sulphur released from vehicular & industrial emissions on mixing with rain water produces acid rain.
2. Traveling in metro (MRTS) instead of fossil fuel driven vehicles.
Associated Value : The learners will adopt Eco-friendly lifestyle so that lesser amount of (No)x and (So)x released into atmosphere which are the main contribution factor causing Acid Rain.
Q . Plastic production is increasing day by day in spite of the fact that plastic is harmful for the environment. Based on the above statement answer the following. 1. What are the harmful effects of plastic usage? 2. In our day to day situation what are the alternatives that we can use instead of plastics.
Ans: Environmental pollution
Burning plastics can cause pollution
Plastic cause harm to the cattle / animals if enter inside their alimentary canal.
ii. Paper bags / jute bags can be used instead of plastic bag.
Any other relevant view of the student
Associated Value : The learners will be discouraged to use plastics as a source of packaging, storing as it is non biodegradable.
Q. With the help of an example show that ‘reuse’ strategy is better than ‘recycling’.
Ans: Reuse strategy is better than recycling. For example, if plastics are sent for recycling, then they would be subjected to melting; causing additional cost of machinery and an unnecessary strain on the energy sources. Also it will lead to environmental pollution. These all factors are ignored during reuse e.g. using the plastic bottles again for drinking water will save the energy.
Q. Construct an aquatic food chain showing four trophic levels. Ans: Hydrilla →Scorpio→ Fish → Crane
Q. To protect the food plants from insects, an insecticide was sprayed in small amounts but it was detected in high concentration in human beings. How did it happen?
As insecticides are not degradable, these get accumulated progressively at each tropic level. As human beings occupy the top level in any food chain, the high concentration of insecticide gets accumulated in their bodies. This phenomenon is known as biological magnification