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KENDRIYA VIDYALAYA PORT TRUST,COCHIN 2021
PERIODIC TEST 3
CLASS 7 SCIENCE m.m 20
1
Name 2 chemicals used to disinfect water
1
2
Device to amplify the sound of heart beat is----
1
3
The process of fusion of male and female gamate is -----
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4
During exhalation the ribs moves---------
1
5
----------- carries oxygen rich blood from the heart to different parts of the body
1
6
Differentiate between self pollination and cross pollination
2
7
What are decomposers ? give two examples
2
8
Name the vascular tissues of the plants,and what are there functions ?
2
9
Explain the function of bar screens in a waste wate treatment plant
2
10
Draw a well labelled diagram of human excretory system
3
11
While 18% of the world’s population resides in India the people have access to only 4% of usable water resources. According to reports about 163 million Indians lack access to safe drinking water.The ground water level is also alarmingly low now. The vagaries of monsoons can have a destructive effect on farmers like deforestation ,population explotion,and mismanagement of drinking water are the some of the reasons. A drought will affect millions of people across the country both directly and indirectly.It's estimated that by 2050, one in four people will lack access to clean drinking water here on Earth. That would be up significantly from an estimated one in ten today. When put into that perspective, it becomes quite clear how dire the world's water crisis really is. Clean water is poised to be one of the world's most important resources in scarcity. 22nd march is celebrated as world water day


QUESTIONS
1 By 2050 what would be the major crisis of the world ? .1M
2 Which day is celebrated as world ware day ? 1M
3What are the major causes of water scarcity ?2 m​

Answer 1

Answer:

baap re itna bada ques. pls wrote in short