Class 10 Science Chapter 15 Our Environment
Are you looking for Class 10 Science Chapter 15 Our Environment notes and question answers? If yes, you are in the right place. This chapter helps students understand the importance of the environment, the relationship between living organisms and nature, and the need to protect our surroundings. It is an important chapter for school exams, HSLC board exams, and competitive examinations.
In this chapter, you will learn about ecosystems, food chains, food webs, producers, consumers, decomposers, biodegradable and non-biodegradable substances, environmental pollution, and waste management. You will also understand how human activities affect the environment and why it is important to conserve natural resources for future generations.
The notes and question answers are written in easy and simple English, making them easy to understand for every student. Each topic is explained in a clear and step-by-step manner, helping students learn faster and revise more effectively before examinations.
Whether you are preparing for class tests, annual examinations, or the HSLC Board Examination, these notes and solutions will help you understand the chapter better, improve your environmental awareness, and score higher marks in Science.
✨ What You Will Get:
- 📘 Easy Chapter Notes
- ❓ Complete Textbook Question Answers
- ⭐ Important Exam Questions
- 📝 Simple and Clear Explanations
- 📚 Quick Revision Notes
- 🎯 HSLC Board Exam Preparation
Start studying Class 10 Science Chapter 15, Our Environment, today and build a strong understanding of environmental science while preparing confidently for your examinations.
Class 10 Science Chapter 15 Our Environment
Selected Questions &Answers
Q: Ozone absorbs …………. (Fill in the blank)
(a) Ultraviolet rays
(b) Infrared rays
(c) Thermal rays
(d) Electromagnetic rays
Ans: (a) Ultraviolet rays.
Q: What is meant by decomposers?
Ans: Microorganisms that can convert the dead bodies of organisms and their wastes into simpler substances are called decomposers.
Q: What are the two main components of an ecosystem?
Ans: Biotic components and abiotic components.
Q: In which category of an ecosystem are bacteria classified?
(a) Producers
(b) Primary consumers
(c) Secondary consumers
(d) Decomposers
Ans: (d) Decomposers.
Q: Give an example of biodegradable waste.
Ans: Mango peel.
Q: Up to what height in the atmosphere does the ozone layer extend?
Ans: The ozone layer extends from about 18 km to 50 km above the Earth’s surface.
Q: What is biopol?
Ans: Materials that are biodegradable and produced with the help of bacteria are called biopol.
Q: Are plastic bags biodegradable waste?
Ans: No.
Q: What prevents ozone in the upper atmosphere?
Ans: Ozone in the upper atmosphere (the ozone layer) is mainly destroyed or prevented from forming properly by certain pollutants, especially chlorofluorocarbons (CFCs).
Q: Write any two possible effects of biodegradable substances on the environment.
Ans: Due to the decomposition of biodegradable substances, flies and other organisms may carry disease-causing germs to food, spreading diseases to humans. The decomposition of these substances also causes air pollution.
Q: Write any two possible effects of non-biodegradable substances on the environment. HSLC 2020
Ans: Some non-biodegradable substances enter the food chain and deteriorate human health. These substances mix with soil and reduce its fertility.
Q: What is a trophic level? Explain the different trophic levels of a food chain with an example. HSLC ’17
Ans: The transfer of food among a group of organisms is called a food chain. This transfer occurs at different levels, which are called trophic levels.
For example, consider a grassland—
Grass→Insects →Fish→Birds
In this chain, grass is the producer and is placed at the first level. Fish areinsect-eaters and are placed at the third level, and birds are higher-level carnivores placed at the fourth level.
Q: What is the role of decomposers in an ecosystem? HSLC ’18
Ans: Decomposers help in converting complex organic substances and living protoplasm into simpler molecules. These molecules mix with the soil and improve its quality. Thus, decomposers help maintain environmental balance.
Q: What is ozone, and how does it affect the ecosystem?
Ans: Ozone is a gaseous molecule made up of three oxygen atoms. It is formed by the reaction between ultraviolet rays from the sun and oxygen. Its effects on the ecosystem are—
(a) It prevents harmful ultraviolet rays from reaching the Earth. These rays can cause cancer and weaken the immune system in humans.
(b) Depletion of the ozone layer affects global temperature.
Q: What steps would you take to reduce the problem of waste disposal? Write any two methods. HSLC ’20
Ans: The problem of waste disposal can be reduced by—
(a) Non-biodegradable materials like plastic and polythene should not be thrown anywhere; they should be properly disposed of or recycled.
(b) Biodegradable wastes should be processed to produce useful biogas.
Q: Which of the following contains only biodegradable substances?
(a) Grass, flowers, and leather
(b) Grass, wood, and plastic
(c) Fruit peels, food items, and sour juice
(d) Food items, wood, and grass
Ans: (a), (c), and (d).
Q: Which of the following forms a food chain? HSLC ’20
(a) Grass, wheat, and mango
(b) Grass, goat, and human
(c) Goat, cow, and elephant
(d) Grass, fish, and goat
Ans: (b) Grass, goat, and human.
Multiple Choice Questions (MCQ)
Q: In the upper layer of the atmosphere, ozone prevents—
(a) Infrared rays
(b) Visible light
(c) Ultraviolet rays
(d) Both (a) and (c)
Ans: (c) Ultraviolet rays.
Q: The flow of energy is always—
(a) Unidirectional
(b) Bidirectional
(c) Cannot be said correctly
(d) None of the above
Ans: (a) Unidirectional.
Q: The cause of diversity in organisms is—
(a) Variation in the environment
(b) Variation in work
(c) Variation in size
(d) Variation in structure
Ans: (a) Variation in environment.
Q: Which of the following is not biodegradable waste?
(a) Kitchen vegetable waste
(b) Old torn clothes
(c) Plastic bag
(d) Old newspaper
Ans: (c) Plastic bag.
Q: Which of the following is a decomposer?
(a) Bacteria
(b) Virus
(c) Algae
(d) None of these
Ans: (a) Bacteria.
Q: Which of the following forms a food chain?
(a) Grass, wheat, and mango
(b) Grass, goat, and human
(c) Goat, cow, and elephant
(d) Grass, fish, and goat
Ans: (b) Grass, goat, and human.
Q: Green plants can produce their own food. Therefore, they are placed at the ………. level of the food chain.
(a) First level
(b) Second level
(c) Third level
(d) Fourth level
Ans: (a) First level.
Q: Which of the following contains only biodegradable substances?
(a) Grass, flowers, and leather
(b) Grass, wood, and plastic
(c) Fruit peels, food items, and sour juice
(d) Food items, wood, and grass
Ans: (a), (c), (d).
Q: Which of the following is a biodegradable waste?
(a) Polythene bag
(b) Mango peel
(c) Torn leather bag
(d) Plastic bottle
Ans: (b) Mango peel
