Extra 30 short answer questions for the chapter:13 "Our Environment" from Class 10 CBSE Science:
What is an ecosystem? Give two examples.
Ans:
An ecosystem is a biological community of interacting organisms and their physical environment. Examples:
Forest, Pond.
Differentiate between biotic and abiotic components with examples.
Ans:
Biotic components
: Living organisms (e.g., plants, animals, bacteria).
Abiotic components
: Non-living things (e.g., water, sunlight, temperature).
What are producers? Give an example.
Ans:
Producers are organisms that make their own food through photosynthesis. Example:
Green plants.
Define decomposers and state their role in the environment.
Ans:
Decomposers break down dead plants and animals, recycling nutrients back into the ecosystem. Example:
Bacteria, fungi.
What is a food chain? Give an example.
Ans:
A food chain shows the transfer of energy from one organism to another. Example:
Grass → Grasshopper → Frog → Snake → Hawk.
What is a food web? How is it different from a food chain?
Ans:
A food web is a network of interconnected food chains in an ecosystem. Unlike a food chain, it shows multiple feeding relationships.
What is meant by trophic level?
Ans:
A trophic level is the position an organism occupies in a food chain, such as
producers, primary consumers, secondary consumers, and decomposers.
What is the 10% Law? Who proposed it?
Ans:
The
10% Law
states that only
10% of energy
is transferred from one trophic level to the next. Proposed by
Raymond Lindeman.
Why do food chains have only 3-4 trophic levels?
Ans:
Due to
energy loss at each level
, a longer food chain would not have enough energy to sustain higher trophic levels.
Why are decomposers necessary in the ecosystem?
Ans:
They break down organic matter, recycle nutrients, and maintain soil fertility.
What are biodegradable and non-biodegradable substances? Give examples.
Ans:
Biodegradable
: Can be broken down naturally (e.g., paper, food waste).
Non-biodegradable
: Cannot be broken down easily (e.g., plastic, glass).
Why are plastic bags harmful to the environment?
Ans:
They are
non-biodegradable
, cause
soil and water pollution
, and harm
animals
when ingested.
What are the causes of ozone layer depletion?
Ans:
Ozone depletion is mainly caused by
CFCs (Chlorofluorocarbons)
found in
aerosols, refrigerators, and air conditioners.
What are the effects of ozone layer depletion?
Ans:
Increased
UV radiation
, causing
skin cancer & cataracts
.
Reduced
crop yield
and weakened
immune system
.
What are greenhouse gases? Name two examples.
Ans:
Greenhouse gases trap heat in the atmosphere. Examples:
Carbon dioxide (CO₂), Methane (CH₄).
What is biomagnification? Explain with an example.
Ans:
Biomagnification is the
increase in toxin concentration at higher trophic levels
. Example: Pesticides like
DDT
accumulating in birds.
What are the harmful effects of excessive use of pesticides and fertilizers?
Ans:
Soil and water pollution.
Kills beneficial microorganisms.
Leads to
biomagnification
in the food chain.
How does deforestation affect the environment?
Ans:
Increases
carbon dioxide
levels, leading to
global warming
.
Causes
soil erosion and loss of biodiversity
.
Why should we avoid using plastic bags?
Ans:
They are
non-biodegradable
,
clog drains
,
pollute soil
, and
harm marine life
when disposed of in water.
What is e-waste? How does it affect the environment?
Ans:
E-waste consists of discarded
electronic devices
like mobiles and computers. It releases
toxic metals
, polluting air, water, and soil.
What are the three R’s of waste management? Explain.
Ans:
Reduce
: Minimize waste production.
Reuse
: Use materials multiple times.
Recycle
: Convert waste into reusable materials.
What is the importance of the ozone layer?
Ans:
It protects life on Earth by absorbing harmful
UV radiation
from the Sun.
How does air pollution affect human health?
Ans:
Causes
respiratory diseases
,
lung cancer
,
asthma
, and
eye irritation
.
What are the major causes of global warming?
Ans:
Excessive
fossil fuel burning
.
Deforestation
, reducing CO₂ absorption.
Increased greenhouse gases.
What are the advantages of using biodegradable materials?
Ans:
They
reduce pollution
,
decompose naturally
, and
do not harm wildlife
.
How can we reduce plastic pollution?
Ans:
Use
cloth or paper bags
.
Ban
single-use plastics
.
Promote
recycling and reusing plastic items
.
What is the effect of deforestation on carbon dioxide levels?
Ans:
Deforestation reduces
oxygen production
and increases
CO₂ levels
, leading to
global warming
.
How can we protect the ozone layer?
Ans:
Reduce
CFC
usage in refrigerators and air conditioners.
Use
ozone-friendly
products.
Promote
tree plantation
to absorb CO₂.
How does excessive use of chemical fertilizers affect soil fertility?
Ans:
Depletes
natural soil nutrients
.
Kills
microorganisms
essential for soil health.
Leads to
water pollution through runoff
.
How does sustainable development help the environment?
Ans:
Uses
resources wisely
for future generations.
Reduces
pollution
and
deforestation
.
Promotes
renewable energy sources
.
