Class 7 chemistry, important questions with answers are provided here for Chapter 17 – Forests: Our Lifeline. These important questions are based on the CBSE board curriculum and correspond to the most recent Class 7 chemistry syllabus. By practising these Class 7 important questions, students will be able to quickly review all of the ideas covered in the chapter and prepare for the Class 7 annual examinations.
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Class 7 Chapter 17 – Forests: Our Lifeline Important Questions with Answers
Very Short Answer Type Questions
Q-1: Floods could result from deforestation. Why?
Answer: Floods result from deforestation because there are fewer trees available as a result of deforestation. Floods will result from the soil’s inability to retain water in the absence of trees.
Q-2: Indicate what happens when one food chain in an ecosystem is harmed.
Answer: Since each food chain in a forest is connected to the others, a disturbance in one food chain will have an impact on the others.
Q-3: What occurs if an animal perishes in the forest?
Answer: Vultures, jackals, hyenas, and other scavengers consume the dead animal’s body. These creatures perform cleaning duties in the forest. Furthermore, it demonstrates that in the forests, nothing is wasted.
Q-4: What do you mean by decomposers?
Answer: Decomposers are microscopic organisms that turn dead plants and animals into humus.
Q-5: Name a system comprising various plants, animals and microorganisms.
Answer: Forest is a system comprising various plants, animals and microorganisms.
Q-6: What does a canopy do?
Answer: A canopy is created by the tall tree’s uppermost branches and leaves, which act as a roof over the forest floor.
Q-7: It gets darker as you move deeper into a forest. Why?
Answer: Large trees, shrubs, and other plants can be found in a forest. They capture solar radiation for photosynthesis. As a result, the forest floor is dark because the sunlight cannot penetrate it.
Q-8: What is a crown?
Answer: The crown of a tree refers to the branchy portion of the tree that is located above the stem.
Q-9: Name a plant from which oil is obtained.
Answer: Sandalwood
Q-10: Name the process by which trees emit water vapour into the atmosphere.
Answer: Evaporation is the process by which trees release water vapour into the atmosphere.
Short Answer Type Questions
Q-1: Why are forests regarded as dynamic living entities?
Answer: The forest offers more opportunities for food and habitat for herbivores by supporting a wider variety of plants. A greater diversity of carnivores can eat more because there are more herbivores. The abundance of animals supports the growth and regeneration of the forest. Decomposers aid in preserving the flow of nutrients to the forest’s expanding plant life. As a result, the forest is a “dynamic living entity”, that is, full of life and vitality.
Q-2: Why are forests called green lungs?
Answer: Plants in the forest produce oxygen through the photosynthesis process. And plants contribute this oxygen to animal respiration. They also keep the atmosphere’s ratio of oxygen to carbon dioxide in check. For this reason, the forests are referred to as green lungs.
Q-3: Would every forest have the same kind of trees?
Answer: No, there are variations in the kinds of trees and other plants due to various climatic conditions. Even animal species vary from forest to forest as well.
Q-4: Where would you find humus in the soil? What significance does it have to the soil?
Answer: Humus is found in the uppermost horizon (A-horizon) and is generally dark in colour as it is rich in humus and minerals. The humus improves soil fertility and gives growing plants nutrients. This layer can hold more water and is typically porous and soft.
Q-5: How would the water cycle affect if there were fewer trees?
Answer: There would be less evaporation and consequently less water vapour in the air if there were fewer trees. Less cloud cover and a higher temperature will result from this. Consequently, there will be less rain. The water cycle will be impacted in this way.
Q-6: How are forests useful in addition to preventing floods?
Answer: Rainwater is naturally absorbed and allowed to seep into the ground by forests. It supports year-round water table maintenance. In order to ensure a consistent supply of water, forests not only assist in reducing floods but also in maintaining the stream’s water flow.
Q-7: Why should forests be protected?
Answer: Forests supply us with oxygen. They protect the soil and provide habitat for a variety of animals. Forests contribute to good rainfall in neighbouring areas. They provide medicinal plants, timber, and a variety of other useful products. Hence, forests must be protected.
Q-8: Is it possible to build a food chain in the absence of a producer? Give a reason to back up your answer.
Answer: No, producers are always at the beginning of any food chain. All living organisms get their food from the producer. If the producer is not present in a food chain, there will be no flow of energy. As a result, we can say that constructing a food chain without a producer is impossible.
Long Answer Type Questions
Q-1: Write the key measures we can take to protect the forest.
Answer: Forests keep nature in balance. Their conservation is urgently needed. To preserve the forests, we should do the following:
- As industrialisation spread, an alarming number of trees were being felled for raw materials and other uses. Selective cutting, clear-cutting, and shelterwood cutting are ways to control this tree-felling.
- To increase the forest cover, more trees should be planted. The geographical conditions of a particular region should be taken into consideration when choosing trees, and care should be taken as they grow.
- For the preservation of the forest, it is essential to prevent the exploitation of forestry and forest products.
- By applying chemicals, antibiotics or creating pest-resistant tree strains, it should be possible to protect the existing forests from diseases.
Q-2: Why should forests be protected?
Answer: Forests supply us with oxygen. They protect the soil and provide habitat for a variety of animals. Forests contribute to good rainfall in neighbouring areas. They provide medicinal plants, timber, and a variety of other useful products. Therefore, forests must be protected.
Q-3: It is said that nothing goes to waste in a forest. Could you explain how?
Answer: Nothing goes to waste in a forest for the following reasons:
- Dry leaves and animal remains are converted into humus, a dark-coloured substance. This gives the plants nutrients.
- Vultures, crows, jackals, and insects feed on dead animals.
- People who live near the forest use broken branches of trees as fuel.
Multiple Choice Type Questions
Q-1: Which of the following forms the lowest layer of vegetation in the forest?
a) Tress
b) Herbs
c) Shrubs
d) None of the above
Answer: b) Herbs
Explanation: In a forest, trees make up the top layer, which is then followed by shrubs. The lowest layer of vegetation is made up of herbs.
Q-2: Which of the following is consumed by an eagle?
a) Insects
b) Frog
c) Snake
d) All of the above
Answer: c) Snake
Explanation: In a food chain, the grass is consumed by insects, which in turn, is taken by the frog for consumption. Snakes consume the frog, and an eagle consumes the snakes.
Q-3: What among the following does not have anything to do with forests?
a) Giving out medicinal plants
b) A rise in Earth’s surface temperature
c) Flood prevention
d) Giving animals food and shelter
Answer: b) A rise in Earth’s surface temperature
Explanation: If forests disappear, the amount of carbon dioxide in the air will increase, resulting in an increase in Earth’s temperature. This demonstrates the value of forests and the fact that forests are not held responsible for a rise in Earth’s surface temperature.
Q-4: Which of the following is not a forest product?
a) Rubber
b) Medicines
c) Kerosene
d) Gum
Answer: c) Kerosene
Explanation: Kerosene is a fossil fuel, whereas rubber, medicines, and gum are items derived from the forests.
Q-5: Which of the following depends mostly on the forests?
a) Animals
b) Plants
c) Tribes
d) All of the above
Answer: c) Tribes
Explanation: Most tribes are highly reliant on the forests. They can find food, shelter, water, and medications in the forest. They have traditional knowledge about many medicinal plants in the forest.
Match the Column Type Questions
Q-1:
| Column I | Column II |
|---|---|
| A) Forests | i) Branchy part of the tree |
| B) Soil | ii) Prevents soil erosion |
| C) Crown | iii) Enhance the growth of the forests |
| D) Trees | iv) Middle layer |
| E) Shrubs | v) Uppermost layer |
Answer: A) – ii), B) – iii), C) – i), D) – v), E) – iv)
Q-2:
| Column I | Column II |
|---|---|
| A) Autotrophs | i) Bacteria |
| B) Heterotrophs | ii) Fish |
| C) Saprotrophs | iii) Algae |
| D) Carnivores | iv) An organism that feeds on plants |
| E) Herbivores | v) An organism that feeds on animals |
Answer: A) – iii), B) – ii), C) – i), D) – v), E) – iv)
