PSEB Punjab Board Class 7 Social Science Textbook Solution Chapter 1 Environment Exercise Questions and Answers
Chapter – 1
Environment
(I) Give answer to the following questions approximately in 1-15 words.
(1) What do you understand by environment?
Ans: Environment is the surroundings and the countless natural forces causing a variety of phenomena on the earth surface, due to which there is a variation in the environment of each place.
(2) Which are the main spheres of environment?
Ans: The major spheres of environment are – Atmosphere, Lithosphere and Hydrosphere.
(3) How do man affects environment?
Ans: Man has made tunnels across the mountains, shipping through manmade canals namely Panama & Suez, diverting the river water for irrigational purposes, exploiting the minerals, and establishing the industrial centres are examples which show that to some extent, man has controlled the natural forces of the earth according to his own requirements.
(4) Write down the names of layers of the earth.
Ans: The earth has mainly three layers – Lithosphere, mantle and the core. The uppermost layer or shell is called SIAL as it mainly consists of Silicon and Aluminium where SI stands for silicon and AL for Aluminium. The second layer is called SIMA and consists of silicon and magnesium. The third and innermost layer is called NiFe which consist of nickle and ferrous.
(II) Fill in the blanks.
(i) Environment has been divided in _____ spheres.
Ans: Three.
(ii) The SIAL layer of the earth is made up of the material which is rich in ____ and ______.
Ans: Silicon, Aluminium.
(iii) NiFe is made up of the material which is rich in _____ and _____ elements.
Ans: Nickle, Ferrous.
(iv) The different types of species of animals is known as ______.
Ans: Animal Kingdom.
(v) _____ portion of Earth has been covered by hydrosphere.
Ans: 71%.