CBE Questions Chapter 15 Our Environment Science Class 10
Hint: Classify biotic and abiotic components and their interaction with each other, in order to describe an ecosystem.
Question.1. The table lists some components of an ecosystem.
A student wants to classify these intoabiotic components from biotic components separately. Which option correctly shows the classification done by the student?
(a) 
(b) 
(c) 
(d) 
Question.2. Which statement shows interaction of an abiotic component with a biotic component in an ecosystem?
(a) A grasshopper feeding on a leaf.
(b) Rainwater running down into the lake.
(c) An earthworm making a burrow in the soil.
(d) A mouse fighting with another mouse for food.
Ans.1. (c) Ans.2. (c) An earthworm making a burrow in the soil.
Hint: Tabulate the organisms feeding on one another (producers, consumers, decomposers) and energy transfer between them, in order to form a food chain or a food web.
Question.3. The table shows some organisms including plants, animals and how they get energy.
Which option shows the correct model made based on the table?
(a) 
(b) 
(c) 
(d) 
Question.4. The image shows a food web.
(a) Fox feeds on hawk obtain energy.
(b) Hawk feeds on oak acorn to obtain energy.
(c) Squirrel feeds on pine borer to obtain energy.
(d) Salamander feeds on pine borer to obtain energy.
Ans.3. (a) Ans.4. (d) Salamander feeds on pine borer to obtain energy.
Hint: Describe the formation & properties of ozone, in order to identify ways to protect it from depletion.
Question.5. The manufacturing of Chlorofluorocarbons free refrigerators is mandatory throughout the world. How this help prevent ozone depletion?
(a) This will help convert oxygen molecules into ozone.
(b) This will help convert the CFCs into ozone molecules.
(c) This will reduce the production of CFC from oxygen molecules.
(d) This will reduce the release of CFCs that reacts with ozone molecules
Question.6. Ozone forms by combination of free oxygen atoms and oxygen molecules. How do free oxygen atoms form at higher levels of atmosphere?
(a) by splitting of molecular oxygen into free oxygen atoms in the presence of low energy UV radiations
(b) by splitting of a molecular oxygen into free oxygen atoms in presence of high energy UV radiations
(c) by the combination of two molecular oxygen in the presence of high energy UV radiations
(d) by the combination of two free oxygen atoms in the presence of lower energy UV radiations
Ans.5. (d) This will reduce the release of CFCs that reacts with ozone molecules
Ans.6. (b) by splitting of a molecular oxygen into free oxygen atoms in presence of high energy UV radiations
Hint: Classify different waste products as biodegradable or non-biodegradable, in order to
assess their effect on environment.
Question.7. The table lists some waste products.
Which group of waste materials can be classified as non-biodegradable?
(a) plant waste, used tea bags
(b) polyethene bags, plastic toys
(c) used tea bags, paper straw
(d) old clothes, broken footwear
Question.8. The table shows some waste materials that changed and remain unchanged when buried in the soil.
What materials correctly classified biodegradable and non-biodegradable materials?
(a) 
(b) 
(c) 
(d) 
Ans.7. (b) polyethene bags, plastic toys
Ans.8. (b)