Class 7: Science Chapter 17 solutions. Complete Class 7 Science Chapter 17 Notes.
Lakhmir Singh Manjit Kaur Solutions for Class 8 Science : Chapter 17- Forests: Our Lifeline
Lakhmir Singh Manjit Kaur 7th Science Chapter 17, Class 7 Science Chapter 17 solutions
(1) Ans:- Decomposers.
(2) Ans:- Crown.
(3) 
Ans:- Two trees are Sal, Mahogany and Two animals are Tiger, Wild Cat.
(4) Ans:- Canopy.
(5) Ans:- The topmost layer of forest is called canopy.
(6) Ans:- Understorey.
(7) Ans:- Shrub layer.
(8) Ans:- Herb layer.
(9) Ans:- Herbs, ferns, grass.
(10)Ans:- True.
(11) Ans:- Saprotrophs.
(12) Ans:- Humus.
(13) Ans:- Canopy.
(14) Ans:- Wood, Timber, Gum, Rubber, and Honey.
(15) Fill in the blanks:
Ans. (a) Lowest
(b) Soil
(c) Soil
(d) air and water.
(e) Pollination
(f) decomposers.
Short Answer Type Questions Solution:
(16) Ans:- The branchy part of a tree above the stem is known as the crown of the tree.
(17) Ans:- The various layer of vegetation in a forest starting from the top downwards are:-
Canopy -> Under Storey -> Shrub Layer -> Herb Layer -> Forest Floor.
(18) Ans:- When an animals die in a forest it was eaten by other animals called scavengers.
(19) Ans:- Trees grows in a natural forest by wind ,water and explosion of trees and by animal.
(20) Ans:- The various effect of destruction of forest are:-
(a) Shortage of wood and other forest product.
(b) Disturbed the balance of Carbon Di Oxide and Oxygen in the Atmosphere.
(c) Soil erosion are caused and making the soil infertile to support crops.
(d) Can change the earth’s climate.
(21) Ans:- It is necessary for conserve forest because:-
(a) to maintain the supply of wood and other products of forest.
(b) maintain the water cycle in nature and bring sufficient rain.
(c) For prevention of Soil erosion and floods. Etc.
(22) Ans:- Paper is made from wood pulp which is produced from the wood. So to make paper many trees have to be cut from the forest. If we are send old newspaper, magazine, unnecessary books to the paper mill for recycling many trees cut will decrease. In this way recycling of paper help in conservation of forest.
(23) Ans:- (i) The dead animals and Animal wastes decay and provide nutrients to the forest soil and make it fertile.
(ii) The animals carry out pollination in flowers and also disperse the seeds of plants and trees throughout the forest.
(24) Ans:- The reason for large scale cutting down of forest trees are to obtain firewood, timber, making paper, agriculture, land of construction of houses, roads, industries, dams etc.
(25) Ans:- The animals which eat dead animals are called scavengers.
The two scavengers are Vulture and Crows.
(26) Ans:- There is no waste in a forest because the animals which are die in a forest are eaten by scavengers (ex: vulture, crow etc.) A well as The decomposer organism decompose the dead plant material, dead animal and animal wastes present in the forest into mineral salts , water and carbon di oxide which go into soil and air.
(27) Ans:- The example food chain taking place in a forest are:-
Grass -> Insect (Grass hopper) -> Frog -> Snake -> Eagle.
(28) Ans:- The humus contains plants nutrients. This humus mixes with the forest soil and make it fertile.
(29) Ans:- The leaves of trees in forest, dead plants, dead animals, animals wastes all are fall on the forest floor. The decomposers organism like fungi, bacteria decompose this organism and to form humus which contains the nutrients. Humus mixes up with soil in the forest and the nutrient present in it fertile it.
(30) Ans:- Follow the Textbook.
Long Answer Type Question Solution:
(31) Ans:- The microorganisms which break down the dead parts of plants and dead bodies of animals into simple substances such as co2, mineral salts etc and which can be re used by plants called decomposers.
The two decomposers are:- Bacteria and fungi.
Decomposers break down the dead parts of plants and dead bodies of animals into simple substances to form humus which contains the nutrients. Humus mixes up with soil in the forest and the nutrient present in it fertile it.
(32) Ans:- The roots of trees and plants growing in the forest bind the particles of top soil and hold the soil together firmly. That’s why binding of soil particles, the strong winds, as well as flowing of rainwater are not able to carry away the top soil.
In the absence of trees the soil particles are not bind by the roots of trees. Hence they are carry away by the rain water, floods, strong winds. Thus Forest prevent soil erosion.
(33) Ans:- Forest acts as a natural absorber of rainwater and allows it to seep. It helps maintain the water table throughout the year. Forests not only help in controlling floods but also help maintain the flow of water in the streams so that we get a steady supply of water. On the other hand, if trees are not present, rain hits the ground directly and may flood the area around it.
(34) Ans:- Forest maintain the balance of carbon di oxide and oxygen in the atmosphere as follows:
The green plants take up carbon di oxide from the atmosphere for making of their food (which are called photosynthesis) and release oxygen during the process of photo synthesis.
Since the green plants and trees of the forest supply oxygen for breathing and respiration. Forest remove carbon di oxide from the atmosphere and put oxygen in the atmosphere Thus forest maintain the balance of oxygen and carbon di oxide.
(35) Ans:- Forest are important for us, other animals and the environment :-
(a) Forest provide many useful products.
(b) It maintain the balance between oxygen and CO2.
(c) Maintaining water cycle in nature.
(d) Keep the climate cool.
(e) It prevent soil erosion.
(f) Prevent occurrence of floods.
(g) It give food, shelter of animals and forest dwelling peoples.
(h) It keep-s the climate cool.
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Lakhmir Singh Manjit Kaur Solutions for Class 7 Science: Chapter 17- Forests: Our Lifeline
Download PDF: Lakhmir Singh Manjit Kaur Solutions for Class 7 Science: Chapter 17- Forests: Our Lifeline PDF
Chapterwise Lakhmir Singh Manjit Kaur Solutions for Class 7 Science :
- Nutrition in Plants
- Nutrition in Animals
- Fibre to Fabric
- Heat
- Acids, Bases and Salts
- Physical and Chemical Changes
- Weather, Climate, And Adaptations of Animals to Climate
- Winds, Storms And Cyclones
- Soil
- Respiration in Organisms
- Transport in Animals and Plants
- Reproduction in Plants
- Motion and Time
- Electric Currents and Its Effects
- Light
- Water: A Precious Resource
- Forests: Our Lifeline
- Wastewater Story
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Students studying under the Central Board of Secondary Education find the textbooks of Lakhmir Singh and Manjit Kaur as one of their go-to textbooks for references. These books are designed based on the latest CBSE syllabus. Every concept that is explained in this textbook comes with supporting examples and problems that give students an opportunity to understand the application of formulas and equations.