NCERT Solutions Class 8 Science Chapter 12: How Nature Works in Harmony (Hinglish)

Grade 8 ki science textbook Curiosity ke Chapter 12, How Nature Works in Harmony, ke Probe and ponder, chapter ke andar ke sawaal, Activities 12.1 se 12.10, Keep the curiosity alive ke saare nau sawaal aur Discover, design, and debate projects ke jawaab. Page numbers 2026-27 reprint ke hisaab se hain (pages 190–209). Chhote notes: Chapter 12 ke notes.

Probe and ponder (page 190)

Haathi kheton mein kyon aate hain? Jab jungle kaate jaate hain aur baarish badalti hai, to hariyaali sookhti hai aur paani ke gaddhe sikudte hain, isliye haathiyon ko apne aavaas mein bhojan aur paani nahi milta aur wo kele aur ganne ke liye kheton aur gaon mein aa jaate hain.

Ghane jungle mein ek ped ka jeevan. Ek ped ke roop mein: mitti se paani aur khanij lena, aksar fungi aur sookshmjeevon ki madad se; bhojan banaane ke liye dhoop aur carbon dioxide lena; oxygen, chhaaya aur pakshiyon aur keedon ko ghar dena; patton aur phalon se jaanvaron ka pet bharna; phoolon ke paraagan ke liye keedon par aur beej failaane ke liye pakshiyon par nirbhar rehna; aur patte giraana jo sadkar mitti ko upjaau banaate hain, jabki jadein mitti ko thaame rakhti hain.

Kya Dharti insaanon ke bina phal-phool sakti hai? Kya insaan Dharti ke bina jee sakte hain? Insaanon se laakhon saal pehle bhi Dharti ke ecosystem phal-phool rahe the. Insaan Dharti ke bina nahi jee sakte, jo hamein hawa, paani aur bhojan sab deti hai.

Ek hi phal ke liye hod karte do tarah ke pakshi. Samay ke saath wo sansaadhan baant sakte hain, alag samay par, ped ke alag hisson par ya alag phal khaakar; ya ek kahin aur chala ja sakta hai ya ghat sakta hai.

Kya insaani kaam praakritik aapdaayein laa sakte hain? Wo unhe zyada baar ya zyada nuksaandeh bana sakte hain: dhalaanon par jungle kaatne se bhooskhalan aur baadh badhte hain, mangrove khatm karne se tat toofaanon ke saamne khule ho jaate hain, aur jalvaayu parivartan lu aur bhaari baarish ko tez karta hai.

Chapter ke andar (pages 191–206)

Activity 12.1 aur talaab. Dono aavaason mein jeevit aur nirjeev hisse hain, alag-alag tarah ke. Machhli ke alaava talaab mein mendhak, kachhue, saanp, dragonfly, machchhar, ghonghe, battakh, shaivaal, diatom, duckweed aur kamal hote hain.

Activity 12.2. Khaali jagah mein apne gine hue paudhe likhiye, jaise usi 1 m² mein 20 ghaas ke paudhon ki population aur sirf 5 genda ke paudhe. Sirf ek tarah ke jeev wala aavaas? Sabko wahi bhojan, paani aur jagah chahiye hogi, isliye hod aur kami hogi; na food chain banegi aur na kachra recycle karne wale decomposers honge.

Activity 12.3. Talaab A mein machhliyaan thi jo dragonfly ke larva khaati hain, isliye wahaan dragonflies kam thi, jo madhumakkhiyaan, makkhiyaan aur titliyaan khaati hain. Talaab A ke paas zyada pollinators ka matlab paas ke paudhon mein zyada beej. Zyada machhli pakadne se dragonflies laut aayengi, pollinators ghatenge aur beej kam banenge, aur machhli khaane wale jaanvaron par bhi asar padega.

Activity 12.4 aur Fig. 12.6. Kriyaayein jeevit aur nirjeev hisson ke beech, do nirjeev hisson ke beech, aur jeevon ke beech hoti hain. Fig. 12.6 mein nadi (jaliya) pahaadon, jungle, ghaas ke maidaan aur khet (sthaliya) ke saath milti hai; khet insaan ka banaaya hai.

Activity 12.5. Sirf ped prakaash sanshleshan karta hai. Hiran aur khargosh paudhe khaate hain; giddh aur shikra jaanvar khaate hain; Bengal lomdi, gilahri aur chooha dono khaate hain; mushroom mare padaarth par jeeta hai. Heterotroph: table mein ped ke alaava sab.

Activities 12.6 aur 12.7. Teer: ghaas → khargosh, ghaas → tiddaa, tiddaa → mendhak, mendhak → saanp, saanp → cheel, khargosh → cheel. Ek aur chain: ghaas → khargosh → cheel. Fasal ke khet mein lagbhag 50 baajre ke paudhe (kuch ped ke peechhe chhipe), lagbhag 15 choohe aur ek cheel hai, jo baajre ko neeche rakhkar piramid banaate hain.

Activity 12.8. Chhoote teer: ghaas → tiddaa, khargosh → lomdi, chooha → baaz, chooha → saanp, mendhak → saanp aur pakshi → baaz. Akela chooha paanch jeevon se juda hai, isliye chains jaal banaati hain.

Kya prakriti sach mein kuch bekaar karti hai? Nahi. Decomposers mare padaarth ke poshak tatva mitti mein lautaate hain, jahaan paudhe unhe phir istemaal karte hain.

Sardiyon ke pakshi. Apne ilaake mein Demoiselle Crane, bar-headed goose, northern pintail aur rosy starling jaise sardi ke mehmaan pakshi dhoondhiye, aur pata kijiye wo kahaan se aate hain.

Activity 12.9: jab hum prakriti mein dakhal dete hain to kya hota hai? Mendhak hataane se keet badhe, jisse zyada keetnaashak daalne pade aur mitti, paani aur sehat ko nuksaan hua; ek insaani kaam poore tantra mein fail gaya.

Fig. 12.16. Madhumakkhi aur phool dono ko faayda (sahopakaarita); orchid ko faayda aur ped par asar nahi (sahbhojita); kilni ko faayda aur kutte ko nuksaan (parjeevita).

Jungle, nadiyaan aur nam-bhoomi kaise bachaayein. Desi ped lagaaiye, jal-sroton mein kachra kabhi mat daaliye, plastic kam kijiye, paani aur bijli bachaaiye, safaai abhiyaanon mein judiye, avaidh kataai ya shikaar ki shikaayat kijiye, aur table jaise sanrakshit kshetron ka samaan kijiye.

Aapke paas ke insaan ke banaaye ecosystem. School ka bageecha, park, machhli ka talaab, khet ya aquarium.

Activity 12.10 aur Green Revolution. Zyada rasaayan bhojan aur paani mein rehkar sehat ko nuksaan pahuncha sakte hain; ye mitti ke sookshmjeev aur humus ghataate hain, keeton ke praakritik shikaari maarte hain aur keeton ko pratirodhi banaate hain, jabki bhaari pumping bhoojal ghataati hai aur ekal kheti pollinators ko nuksaan pahunchaati hai. Madadgaar tareeke: jaivik khaad aur compost, fasal chakra aur mishrit fasal, mitti upjaau karne wali dalhan, praakritik keet niyantran, samajhdaari se sinchaai aur kam jutaai.

Keep the curiosity alive (pages 207–208)

1. (iii) galat hai: ecosystem samudaay ka hissa nahi; samudaay ecosystem ka hissa hai.

2. Mare paudhe, jaanvar aur kachra jama hote jaate, aur unke poshak tatva unhi mein band rehte. Mitti dheere-dheere urvarta kho deti, paudhe kamzor padte, aur phir unpar nirbhar jaanvar. Decomposers zaroori hain kyonki wo poshak tatva recycle karte hain aur maahaul saaf rakhte hain.

3. Mangrove tat ke saath ghani patti mein ugte hain. Unki uljhi jadein aur tane lehron ko dheema karte hain aur mitti thaamte hain, isliye tsunami zameen tak pahunchne se pehle apni bahut taakat kho deti hai. Mangrove ke peechhe bas Selvam ke gaon par, bina mangrove wale gaon se kam maar padi.

4. Tidde badh jaayenge, kyonki unhe koi nahi khaayega, aur phir zyada ghaas kha sakte hain; saanp ghat jaayenge kyonki unka bhojan chhin jaata hai, jab tak wo doosra shikaar na dhoondh lein.

5. Sambhaavit kaaran: bageeche mein keetnaashak, ras dene wale phool kam hona, illiyon ke khaane wale paudhe hat jaana, ya garam, sookha mausam. Kadam: genda, zinnia aur ixora jaise ras bhare phool ugaaiye; lime butterfly ke liye kadi patta aur neebu jaise illiyon ke khaane wale paudhe lagaaiye; keetnaashak chhidakna band kijiye; aur ek nam, keechad bhari jagah chhodiye.

6. Akele utpaadak nahi tik sakte. Decomposers ke bina mara padaarth jama hota aur poshak tatva mitti mein nahi lautte, isliye utpaadak aakhir mein poshan ke bina bhookhe rehte; upbhoktaon ke bina jaanvar pollinator ya beej failaane wale nahi hote aur paudhon ki badhat par roak nahi hoti.

7. Park mein ped, ghaas, phool, pakshi, gilahri aur keede, mitti, paani aur chhaaya ke saath hote hain; sadak kinaare kuch paudhe dhool, dhuaan, shor, garmi aur concrete ke saath. Park kahin zyada jeevan aur kriyaaon ko sahaara deta hai.

8. Khet zaroori hain kyonki wo hamein khaana dete hain. Par rasaayanon, bhoojal aur ekal kheti ka zyada upyog mitti bigaadta hai aur pollinators aur praakritik shikaariyon ko nuksaan pahunchaata hai, isliye khet jaivik khaad, fasal chakra, mishrit fasal, praakritik keet niyantran aur samajhdaari ki sinchaai se tikaau banaane chahiye.

9. Khargosh khaane wali lomdiyon ko bhojan kam padega aur wo ghatengi ya doosra shikaar karengi. Ghaas aur paudhe zyada badhenge; hiran ko zyada bhojan milega aur wo badh sakte hain, aur hiran khaane wali cheelein bhi.

Discover, design, and debate (pages 208–209)

Safaai ka din. Aam taur par plastic ke rapper aur botalein sabse zyada milti hain. Inhe kam karne ke liye apni bottle aur dabba saath rakhiye, ek baar wale plastic ko na kahiye, alag-alag kooda-daan rakhiye aur recycle kijiye.

Janjaatiyaan aur jaanvar. Nyishi, Mishmi aur Baiga ke alaava Rajasthan ka Bishnoi samudaay kaale hiran aur chinkara ki raksha ke liye jaana jaata hai, aur Nilgiri ke Toda logon ki sanskriti mein bhainson ki khaas jagah hai.

Ek ped ko dekhna. Har hafte naye patte, phool, phal aur aane wale pakshi-keede note kijiye, aur citizen scientist ke roop mein SeasonWatch par saajha kijiye.

Khet ki yaatra aur Fig. 12.21. Tasveer mishrit kheti dikhaati hai: gobar ki khaad ke liye pashu, bailon se jutaai, mili-juli fasal ka khet, ghar ka bageecha, murgiyaan aur phal ke ped. Sujhaav: compost aur kenchua khaad, fasal chakra, mishrit fasal, neem se bane chhidkaav, aur baarish ka paani jama karna.