Chapter 15

āĻ…āϧ্āϝাāϝ় ā§§ā§Ģ

Our Environment

āφāĻŽাā§° āĻĒā§°িā§ąেāĻļ

EXERCISES

āĻŦ্āϝাāϝ়াāĻŽ

 1. Which of the following groups contain only biodegradable items?

ā§§/ āϤāϞ⧰ āĻ•োāύāϟো āĻ—োāϟāϤ āĻ•েā§ąāϞ āϜৈā§ą-āĻŦিāϘ্āύিāϤ āϏাāĻŽāĻ—্ā§°ীāĻšে āĻĨাāĻ•ে?

 (a) Grass, flowers and leather

(āĻ•) āϘাঁāĻš, āĻĢুāϞ āφ⧰ু āϚাāĻŽā§°া

 (b) Grass, wood and plastic

(āĻ–) āϘাঁāĻš, āĻ•াāĻ  āφ⧰ু āĻĒ্āϞাāώ্āϟিāĻ•

 (c) Fruit-peels, cake and lime-juice

(āĻ—) āĻĢāϞ⧰ āĻ–োāϞা, āĻ•েāĻ• āφ⧰ু āϚূāĻŖā§° ā§°āϏ

 (d) Cake, wood and grass

(āϘ) āĻĒিāĻ া, āĻ•াāĻ  āφ⧰ু āϘাঁāĻš

 Ans-


2. Which of the following constitute a food-chain?

⧍/ āϤāϞ⧰ āĻ•োāύāϟোā§ąে āĻ–াāĻĻ্āϝ-āĻļৃংāĻ–āϞ āĻ—āĻ āύ āϕ⧰ে?

 (a) Grass, wheat and mango

(āĻ•) āϘাঁāĻš, āϘেঁāĻšু āφ⧰ু āφāĻŽ

 (b) Grass, goat and human

(āĻ–) āϘাঁāĻš, āĻ›াāĻ—āϞী āφ⧰ু āĻŽাāύুāĻš

 (c) Goat, cow and elephant

(āĻ—) āĻ›াāĻ—āϞী, āĻ—ā§°ু āφ⧰ু āĻšাāϤী

 (d) Grass, fish and goat

(āϘ) āϘাঁāĻš, āĻŽাāĻ› āφ⧰ু āĻ›াāĻ—āϞী

  Ans-


3. Which of the following are environment-friendly practices? 

ā§Š/ āϤāϞ⧰ āĻ•োāύāĻŦোā§° āĻĒā§°িā§ąেāĻļ-āĻŦāύ্āϧুāϤ্āĻŦāĻĒূā§°্āĻŖ āĻĒāĻĻ্āϧāϤি?

(a) Carrying cloth-bags to put purchases in while shopping

(āĻ•) āĻŦāϜাā§° āϕ⧰াā§° āϏāĻŽāϝ়āϤ āĻ•্ā§°āϝ় āϕ⧰া āĻŦāϏ্āϤু āĻĨ’āĻŦāϞৈ āĻ•াāĻĒোā§°-āĻŦেāĻ— āĻ•āĻĸ়িāϝ়াāχ āύিāϝ়া

(b) Switching off unnecessary lights and fans

(āĻ–) āĻ…āĻĒ্ā§°āϝ়োāϜāύীāϝ় āϞাāχāϟ āφ⧰ু āĻĢেāύ āĻŦāύ্āϧ āϕ⧰া

 (c) Walking to school instead of getting your mother to drop you on her scooter

(āĻ—) āĻŽাāĻ•ে āϤোāĻŽাāĻ• āϏ্āĻ•ুāϟীāϤ āύāĻŽাāχ āĻĻিāϝ়াā§° āĻĒā§°িā§ąā§°্āϤে āĻ–োāϜāĻ•াāĻĸ়ি āϏ্āĻ•ুāϞāϞৈ āϝোā§ąা

 (d) All of the above

(āϘ) āĻ“āĻĒā§°ā§° āϏāĻ•āϞোāĻŦোā§°

  Ans-


4. What will happen if we kill all the organisms in one trophic level?

ā§Ē/ āφāĻŽি āϝāĻĻি āϏāĻ•āϞো āϜীā§ąāĻ• āĻāϟা āϟ্ā§°āĻĢিāĻ• āϞেāĻ­েāϞāϤ āĻŽাā§°ি āĻĒেāϞাāĻ“ঁ āϤেāύ্āϤে āĻ•ি āĻš’āĻŦ?

  Ans-


5. Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?

ā§Ģ/ āĻāϟা āϟ্ā§°āĻĢিāĻ• āϏ্āϤ⧰āϤ āĻĨāĻ•া āϏāĻ•āϞো āϜীā§ą āφঁāϤ⧰োā§ąাā§° āĻĒ্ā§°āĻ­াā§ą āĻŦিāĻ­িāύ্āύ āϟ্ā§°āĻĢিāĻ• āϏ্āϤ⧰⧰ āĻŦাāĻŦে āĻŦেāϞেāĻ— āĻš’āĻŦāύে? āĻĒā§°িā§ąেāĻļ āϤāύ্āϤ্ā§°ā§° āĻ•োāύো āϧ⧰āĻŖā§° āĻ•্āώāϤি āύāϕ⧰াāĻ•ৈ āϝিāĻ•োāύো āϟ্ā§°āĻĢিāĻ• āϏ্āϤ⧰⧰ āϜীā§ąāĻŦোā§° āφঁāϤ⧰াāχ āĻĒেāϞাāĻŦ āĻĒাā§°িāύে?

  Ans-


6. What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?

ā§Ŧ/ āϜৈā§ąিāĻ• āĻŦৃāĻĻ্āϧি āĻ•ি? āĻĒā§°িā§ąেāĻļ āϤāύ্āϤ্ā§°ā§° āĻŦিāĻ­িāύ্āύ āϏ্āϤ⧰āϤ āĻāχ āĻŦৃāĻĻ্āϧিā§° āĻŽাāϤ্ā§°া āĻŦেāϞেāĻ— āĻŦেāϞেāĻ— āĻš’āĻŦāύে?

  Ans-


7. What are the problems caused by the non-biodegradable wastes that we generate?

ā§­/ āφāĻŽি āĻ‰ā§ŽāĻĒāύ্āύ āϕ⧰া āĻ…āϜৈā§ą-āĻŦিāϘ্āύিāϤ āĻ†ā§ąā§°্āϜāύাāĻŦোā§°ā§° āĻĢāϞāϤ āĻ•ি āĻ•ি āϏāĻŽāϏ্āϝাā§° āϏৃāώ্āϟি āĻšāϝ়?

  Ans-


8. If all the waste we generate is biodegradable, will this have no impact on the environment?

ā§Ž/ āφāĻŽি āĻ‰ā§ŽāĻĒāύ্āύ āϕ⧰া āϏāĻ•āϞো āĻ†ā§ąā§°্āϜāύা āϝāĻĻি āϜৈā§ą-āĻŦিāϘ্āύিāϤ āĻšāϝ় āϤেāύ্āϤে āχāϝ়াā§° āĻĒā§°িā§ąেāĻļāϤ āĻ•োāύো āĻĒ্ā§°āĻ­াā§ą āύāĻĒā§°েāύে?

  Ans-


9. Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

⧝/ āĻ…’āϜāύ āϏ্āϤ⧰⧰ āĻ•্āώāϤি āĻ•িāϝ় āϚিāύ্āϤাā§° āĻ•াā§°āĻŖ? āĻāχ āĻ•্āώāϤি āϏীāĻŽিāϤ āϕ⧰িāĻŦāϞৈ āĻ•ি āĻĒāĻĻāĻ•্āώেāĻĒ āĻ—্ā§°āĻšāĻŖ āϕ⧰া āĻšৈāĻ›ে?

  Ans-