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Diti Sharma from Amity International School, Noida
Subject :NSO    Class : Class 8

Air pollutants are harmful to living things. Which of the following is/are their harmful effect(s)?
(i) They form acid rain.
(ii) They cause breathing problems in humans.
(iii) They interfere with photosynthesis in plants.
(iv) They result in the depletion of ozone layer.

A (i) only
B (i) and (ii) only
C (i), (ii) and (iii) only
D (i), (ii), (iii) and (iv)


It is because acid rain is caused by sulphur dioxide and nitrogen dioxide. Breathing problems are caused by various kinds of pollutants. Dust particles interfere with photosynthesis in plants. Chloro-fluoro carbons or CFCs result in the depletion of ozone layer.

Ans 1:

Pratyay Anand from Ryan International School, NAVI MUMBAI
Class : Class 8
i dont understand how ?

Ans 2:

Ayush Anand Sharma from GEMS international school , Gurgaon
Class : Class 8
Please explain

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Drashti from Global Indian International School, Noida
Subject :NSO    Class : Class 7

Ans 1:

priyanka from kendriya vidalaya kathmandu, JHAJJAR
Class : Class 8
option b

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ANURADHA NAIR from SANDEEPANI VIDYA NIKETHAN SCHOOL, Thrissur
Subject :NSO    Class : Class 4

Ans 1:

Payal Porwal from St John gola, Gola
Class : Class 6
C

Ans 2:

Ridhan from SFS janakpuri, New Delhi
Class : Class 5
answer is a because when the ice melts it becomes warmer and changes into liqiud

Ans 3:

ANURADHA NAIR from SANDEEPANI VIDYA NIKETHAN SCHOOL, Thrissur
Class : Class 5
A IS THE ANSWER

Ans 4:

Kanav Dhingra from DPS sec45, Gurgaon
Class : Class 6
option A

Ans 5:

sauradeep from j v m Shyamali , ranchi
Class : Class 6
C

Ans 6:

Payal Porwal from St John gola, Gola
Class : Class 6
C

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xyz from cambridge, Jalandhar
Subject :NSO    Class : Class 3

Ans 1:

xyz from cambridge, Jalandhar
Class : Class 7
The correct answer is A

Ans 2:

Iraj Singh from DPS Megacuty, Kolkata
Class : Class 4
The correct answer is A only.

Ans 3:

ANSHUL GAJJAR from PODAR INTERNATIONAL SCHOOL, AHMEDABAD
Class : Class 3
A

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MAHESH PRASAD MC from Silveroaks, Hyderabad
Subject :NSO    Class : Class 8

Ans 1:

visagan santhanam from sacred heart school, VILLUPURAM
Class : Class 8

Ans 2:

visagan santhanam from sacred heart school, VILLUPURAM
Class : Class 8

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tamojit das from techno India Group Public School , Chinsura
Subject :NSO    Class : Class 8

Ans 1:

Nilanjana De from Delhi Public School North, Bengaluru
Class : Class 8
The solution says that the answer is supposed to be d but according to the explanation given the answer seems to be a. Please explain.

Ans 2:

Arnav Ranka from Gyan Bharati School, Saket, New Delhi
Class : Class 8

Ans 3:

Karthik Rao Varam from Bala Vidya Mandir, Chennai
Class : Class 8

Ans 4:

S V Harini from Vailankanni public school , Krishnagiri
Class : Class 8

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Antara Mazumdar from Navy Children School, Mumbai
Subject :NSO    Class : Class 7

Ans 1:

Amol Athawale from WoodRidge High, aurangabad
Class : Class 8
this question did not come in the question paper,when i was solving

Ans 2:

Spandan Pradeep Pathare from Takshila school , Ahmednagar
Class : Class 8
Answer is option a as decomposition of dead matter of plant and animal by animals which gives nutrients to plants

Ans 3:

Jai kumar Bohara from Dps, Udaipur
Class : Class 9
this question did not come in the question paper,when i was solving

Ans 4:

rachith from null, null
Class : Class 7
this q didnt come

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JANANI DINESH from CHINMAYA VIDYALAYA VIRUGAMBAKKAM, CHENNAI
Subject :NSO    Class : Class 3

Ans 1:

Siddhant from Gundecha Education Society, Mumbai
Class : Class 3
D - Because increase in plant also increases population of Caterpiler and Grasshopper, and decrease in snake may constant Bulbul population if plant did not increases.

Ans 2:

Mohi from Vibgyor, Bangalore
Class : Class 1
B

Ans 3:

Sourish Mahakul from Delhi Public School Electronic City, Bengaluru
Class : Class 4
answer is c

Ans 4:

Adya Shree from Shishya BEML Public School, Bangalore
Class : Class 3

Ans 5:

ANSHUL GAJJAR from PODAR INTERNATIONAL SCHOOL, AHMEDABAD
Class : Class 3
C

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xyz from cambridge, Jalandhar
Subject :NSO    Class : Class 5

Ans 1:

Hari Govind from Delhi Public School Chandigarh , Chandigarh
Class : Class 6
d

Ans 2:

xyz from cambridge, Jalandhar
Class : Class 7
B

Ans 3:

Ira Jamsandekar from Shantiniketan, KOLHAPUR
Class : Class 6
Single pulley does not provide any mechanical advantage, it only changes the direction of force while an inclined plane provides mechanical advantage. This means the efforts required to life the same amount of load on an inclined plane is lesser than that by a single pulley. (Pulley provides mechanical advantage only if we use more than one pulley).Lesser the inclination more is mechanical advantage and lesser the effort. That means the correct answer should be 'D'

Ans 4:

Samarth Sabari from GIIS, Singapore
Class : Class 5
B

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xyz from cambridge, Jalandhar
Subject :NSO    Class : Class 5

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