Extra Questions for Class 10th: Ch 15 Our Environment (Science) Important Questions Answer Included
Very Short Answer Questions (VSAQs): 1 Mark
Q1. Why is excessive use of CFCs a cause of concern?
Answer
When CFC'S reach upper layers of the atmosphere, they cause depletion of ozone layer, and allow harmful UV radiations to reach the surface of the earth to create health hazards.
Q2. Name the gas which is produced due to incomplete combustion of fossil fuel.
Answer
Carbon monoxide.
Q3. Select the item which is made up of biodegradable material — Plastic bag, leather bag, nylon rope, kettle.
Answer
Leather bag.
Q4 Name the gas which is produced due to incomplete combustion of fossil fuel.
Answer
Carbon monoxide.
Q5. List two natural ecosystems.
Answer
Forest, Lake
Short Answer Questions
Q1. Write the appropriate name of the tropical levels X and Y, with an example?
Answer
(a) X is producer. Example- green plants
(b) Y is tertiary. Example-Hawk
Q2. Accumulation of harmful chemicals in our bodies can be avoided. Explain how this can be achieved ?
Answer
We should drink plenty of water, eat healthy food, perform exercise and do not take stress to avoid accumulation of harmful chemicals in our body.
We should eat more vegetables especially cruciferous vegetables (such as broccoli, cauliflower, etc.) than meat so that biological magnification will be least.
Q3. List two reasons to show that the existence of decomposers is essential in an ecosystem.
Answer
(i) They help in the breakdown of organic matter or biomass of dead plants and animals into simple inorganic raw materials such as CO2, H2O and nutrients.
(ii) They help in the natural replenishment of soil.
Q4. Energy flow in food chain is unidirectional. Justify the statement.
Answer
In a food chain the energy moves progressively through the various trophic levels and is no longer available to the organisms of the previous trophic level/ energy captured by the autotrophs does not revert back to the solar input.
Q5. We do not clean ponds or lakes, but an aquarium needs to be cleaned. Why?
Answer
Ponds and lakes are natural ecosystem and they have self-cleaning mechanism due to food chain and other environmental factors. But, an aquarium being an artificial eco-system do not have such mechanism. Therefore, we need to clean aquarium.
Q6. We often observe domestic waste decomposing in the bylanes of residential colonies. Suggest ways to make people realize that improper disposal of waste is harmful to the environment.
Answer
(i) Special sessions or festival on environmental theme should be called by colony local administrative bodies.
(ii) Street plays and short movies should be prepared highlighting the ill effects of improper disposal of wastes.